Finding Max Loads in Revolvers

[ultramag]

I'd like to start a discussion on safely working to max loads in revolvers. To head off some of the comments that invariably crop up when this question is posed I'm not a speed demon or someone who thinks if my bullet is going 50 feet per second faster I'll be able to shoot my deer in the knee and still kill it.....it's all about chasing the most accurate load that brings me to this question.

I've been shooting my revolvers like crazy the last 6 months after discovering the joys of shooting cast bullets in them. I'm working diligently to become more proficient than ever with my revolvers in order to hunt deer with them this fall. This is something I've had in mind for years and I've just never been prepared when it's time to go to the woods in the fall.....not this year!

In this process I've found several loads that I've taken to the edge of published data and in a couple cases 1/2 of a grain over max and they just keep shooting better. In addition to this I've been working with Clays in the .454 Casull in spite of their being no load data for this combo. I've extrapolated data to this point from the .45 Colt and burn rate comparisons to powders used in known loads. I've carefully worked up to a 7.0 gr. charge of Clays under a Lee .452 TL TC bullet that drops at 240 grains with my alloy. I started at 6.0 gr. and it just keeps getting better as I increase the charge weight. It's my hypothesis at this point that there is quite possibly 2-3 grains more to go here. I admit to being quite hesitant as I'm basically flying blind. I've had great luck with Clays in the .44M so far though with cast boolits and read similiar reports for the .45 Colt. This is what gave me the desire to try it in .454 Casull in the first place.

I used to always pay attention to how the cases came out of the cylinder as I worked up loads before but in the course of researching this topic have found several sources that claim once you have difficult extraction from the cylinder you are WAY over safe chamber pressures. My next two thoughts are setting up the chronograph as a guide and/or measuring case head expansion. Are these reliable indicators? Is there a better way? Does anyone here have any experience in truly finding a max load in their own revolver? I'm not really wanting to be a tenth of a grain from disintegration or anything nuts like that....I just want to get the most from my loads, mainly accuracy wise, and of course whatever gains come from velocity etc. are welcome as well.

I hope this post can be taken in the spirit that it is meant and not turn into a lecture. I have enough faith in the members here and the way they treat each other to at least try to discuss this topic here. It's taken me a couple weeks to decide to go ahead and post this though.

[Love Life]

To find a max load? If working with established data I just keep on going up in charge weight until the brass and firearm tell me to stop.

For unpublished data with a new powder I take the same steps as you.

You actually have it pretty wel figured out and I would keep on keeping on if I were you.

[jsheyn]

Pretty much use published data and work up from the max in .2gn incriments until I see signs of to much preasure. I also make sur eto shoot from a supported rest and will get a relative acuaracy result.

[44man]

I know of no reliable method to reach a pressure limit in revolvers. I do know a stuck case is way too much but another revolver will eat that load like it was nothing.
Too much variation in dimensions so case expansion and primer indications mean little.
Some powders will spike with a small addition while others can go over max listed loads.
I just don't know how to identify a load too hot except by a sticky case and that might not happen ever in some revolvers until it is scrap metal.
If you think a powder can go 2 to 3 gr more, forget it, it might just spike and ruin your day.
Sorry, but I can not explain load limits.

[ultramag]

If working with established data I just keep on going up in charge weight until the brass and firearm tell me to stop.


And the brass and firearm tells you to stop how???

[Jeff82]

+1 with 44man's comments. I don't know what you're shooting, but Rugers are factory testing at loadings that are 1.3 to 1.5x rated pressure. One word of caution is that you might find that your gun might be able to handle a higher than rated pressure loading. However, a steady diet of which may eventually ruin your weapon.

Also, rather than pushing Clays to the limit, you might try Clay's Universal. It burns slower and can develop more velocity before reaching peak pressure. This may cost you a bit in accuracy though as compared to Titegroup for instance. But, if you're looking for f-lbs for hunting,.....

As far as what the brass may tell you, if you find that the primer is pressed flat or that the base of the cartridge is imprinted by the breach, you're pushing more pressure than the casing and primer are designed for. Whether this indicates that you're pushing too much pressure for the weapon is not neccesarily the case. However, if all things are truly designed around pressure ratings, that would be the case.

[subsonic]

The best indicators are the factory manuals. There's no free lunch. If you are getting more velocity than the books show, or the same velocity in a shorter barrel, there's a 99% chance that you are over the pressure limit of the SAAMI data for the caliber.

Unfortunately, the SAAMI data may not have been set in regards to the firearm you are working with, but the WEAKEST firearm available in that caliber.

For example, .44 mag data has to be safe in any .44 mag factory firearm. The loads that a S&W 29 can eat reguarly are quite a bit different than the loads an 1894 Marlin can stand, or that a 5 shot .44 mag BFR can stand...

Brass is brass to some degree, but firearms are different.

Most of the "indicators" like flat primers, sticky extraction, and bulged cases can be caused by other things. But I can assure you that if you have high pressure, you will have at least one of those symptoms if not all of them. Of course, some calibers are allowed to run at those pressures, such as the .454 Casull. Tight chambers and tight headspace can minimize pressure signs, but only so much.

[Love Life]

And the brass and firearm tells you to stop how???

VIA a toll free telephone number.

[ultramag]

VIA a toll free telephone number.

I guess I'm not sure what this kind of nonsense is supposed to prove or how it's supposed to help??? :confused: :confused:

What the signs you use are and how you read them and utilize those readings are the very essence of what this question is about. You've posted twice now within this thread but you don't want to elaborate, instead choosing to crack wise about phone calls to your revolvers and brass??? :confused: :confused:

[Kull]

I've worked at finding max loads for Ruger's flattop convertable. It's been the same process as what your doing. Gather as much info as possible, from as many sources as possible. Extrapolate and verify with your own tests. You mentioned a chronograph....you do have a chronograph yes? Ken Waters used a chrony and case head measurements in his tests to find max loads. His book, Pet Loads, is an interesting book. Not so much for the data as for the methodology, and it's just a nice read too. The whole measuring case head thing is a debated topic. This is the area Quickload begins to be worth some of it's price. Not as a guide, I'd never trust it alone, but as a sanity check. It can also save you some money by narrowing down powder choices to those most appropriate. Clay's isn't appropriate for 454 Casull.

[tchepone]

Ultramag: I do a fair amount of what you are asking about, namely trying to find the most accurate load which any of my guns will produce, through experimentation. Some times this takes me beyond what published data tells me is safe. Published date is a guide, not a gospel on the characteristics and capabilities of any gun. The published data are usually loads that are safe in the weakest gun that is commonly available. I have a few that will exceed the published data without issues. I have others that exhibit pressure signs before I get to published maximum. In the greatest majority of loads I find the most accurate load just below the maximum published data.
I have not found any reliable and repeatable way to ascertain when you are at the maximum pressure any gun will withstand. There are just too many variables. This is especially the case with a revolver. I’m sure there is a way, with the proper pressure recording equipment, but that is probably way beyond the average shooters understanding and pocketbook.
Approach the subject using a methodology that you can follow and repeat to verify. Have some way to clearly record the data you obtain. Make sure you do your research before you ever fire a shot. There are literally thousands of articles, on almost every cartridge ever fired, available for you to study. Study the bullet weight, type, alloy and amount of bearing surface, to powder speed and caliber relationship. When you approach the foggy regions, make sure you are using good quality cases, preferably new or at least documented once fired.
I rely on all the things you mentioned, case head expansion, extraction, primer and case head appearance. In addition I use recoil and muzzle blast. These items, all taken together, “may” warn you of impending doom. You must pay attention to what is happening with each and every shot. Consistent gripping, support and follow through with each shot will tell you a lot about that shot. This is not a rapid fire exercise. I use a quality Oehler chronograph. Read about and understand what the chronograph is trying to tell you, don’t just look for maximum velocity. Read, Record, Reload, Re-verify.
I hope the foregoing didn’t sound too much like a lecture. These process’s can be trying, fun and knowledge gaining, but proceed with caution.. Happy accurate shooting.
BTW, I agree, Clays is not a proper powder for use with the 454 Casull....G

[Love Life]

UltraMag- You have all the answers already. I do not say that in a smart aleck way at all. You have taken a very methodical approach.

To answer your question: Flattened primers, cratered primers, and hard extraction are all telling you something. Your brass and revolvers are telling you to back down.

[44man]

I guess I'm not sure what this kind of nonsense is supposed to prove or how it's supposed to help??? :confused: :confused:

What the signs you use are and how you read them and utilize those readings are the very essence of what this question is about. You've posted twice now within this thread but you don't want to elaborate, instead choosing to crack wise about phone calls to your revolvers and brass??? :confused: :confused:
There is a kind of truth in what he said. You must understand that all of us here will not go where Angels fear to tread.
A toll free call to the Lord might be needed. God will not protect fools, not his job.
You were told readings for pressure will vary and some will not show up until you are on the way to the hospital.
Be more tolerant, we care for your safety.
Loading your own is very safe but if you think you can go beyond, it is so dangerous it is unreal.
I still have fear with new guns. Fear is a friend. I never need the toll free call.

[Rodfac]

44Man....very well said...couldn't agree more...Rod
I know of no reliable method to reach a pressure limit in revolvers. I do know a stuck case is way too much but another revolver will eat that load like it was nothing.
Too much variation in dimensions so case expansion and primer indications mean little.
Some powders will spike with a small addition while others can go over max listed loads.
I just don't know how to identify a load too hot except by a sticky case and that might not happen ever in some revolvers until it is scrap metal.
If you think a powder can go 2 to 3 gr more, forget it, it might just spike and ruin your day.
Sorry, but I can not explain load limits.

[Larry Gibson]

44man said it very well.

My advice, unless you have the ability to actually measure the pressure, is to stay within load data of newer reloading manuals.

I proffer that advice because I can and do measure the psi in many revolver cartridges. I have tested numerous loads with cases that extracted easily from revolver chambers and the primers exhibited no sign of excess psi yet they were indeed quite a bit over the SAAMI MAP for magnum cartridges let alone standard cartridges.

Stay within the data of newer loading manuals.

Larry Gibson

[Tatume]

One additional bit of information helps judge pressure, velocity. When I work up loads I chronograph them as I go. If my velocities approach the book maximum velocity, I stop. As a cautious reloader, I do not want anything to do with max loads. Sometimes velocities will be at or near book maximum while powder charge weight is well below the listed maximum. For example, if the book maximum with a 300 grain Hornady HP-XTP bullet is 1200 fps in a 7-1/2 44 Rem Mag Ruger BH (Hornady 6e), and I record 1150 fps with 19.0 gr H110, I'm done. Even though the book max is 20.1, my chronograph told me to stop, and I do.

On the other hand, if I were to reach 20.0 gr H110 with that bullet and my velocity reading was 1150 fps, I would also stop. The book says 1200 fps, and I can't safely achieve it. So what? I'm perfectly satisfied with a SAFE 1150 fps.

My opinion, a chronograph is an invaluable piece of equipment.

Take care, Tom

[44MAG#1]

Has anything been solved yet that most long time reloaders don't know already?
If someone asks how to judge pressure signs it makes me wonder if they would know how even if someone explained it to them.
There are some things that one needs to learn by actual experience. And no someone doesn't need to blow up a gun in order to lean.
And another thing in over 40 years of loading especially now that piezo transducer methods are used I have never found a recommended load by anyone such as Speer, Hornady, that has recommended a load that was max that was too much in any of the cailber of handguns I have loaded for and there have been several. Provided I used their prescribed load and didn't substitute other components.
Will I run into that one day? Maybe so but that is the reason one never starts with max in anything. But even there one can. I remember one chap that wrote in and asked if a max 38 Special load would hurt his revolver and when asked about the gun it was a 357 Mag.
Sometimes the best fiction writer in the world couldn't make up some things people come up with.

[Jeff82]

44man said it very well.



I proffer that advice because I can and do measure the psi in many revolver cartridges. I have tested numerous loads with cases that extracted easily from revolver chambers and the primers exhibited no sign of excess psi yet they were indeed quite a bit over the SAAMI MAP for magnum cartridges let alone standard cartridges.

Stay within the data of newer loading manuals.

Larry Gibson

Larry, very interesting. How are you set up to do this?

--Jeff

[ultramag]

Ultramag: I do a fair amount of what you are asking about, namely trying to find the most accurate load which any of my guns will produce, through experimentation. Some times this takes me beyond what published data tells me is safe. Published date is a guide, not a gospel on the characteristics and capabilities of any gun. The published data are usually loads that are safe in the weakest gun that is commonly available. I have a few that will exceed the published data without issues. I have others that exhibit pressure signs before I get to published maximum. In the greatest majority of loads I find the most accurate load just below the maximum published data.
I have not found any reliable and repeatable way to ascertain when you are at the maximum pressure any gun will withstand. There are just too many variables. This is especially the case with a revolver. I’m sure there is a way, with the proper pressure recording equipment, but that is probably way beyond the average shooters understanding and pocketbook.
Approach the subject using a methodology that you can follow and repeat to verify. Have some way to clearly record the data you obtain. Make sure you do your research before you ever fire a shot. There are literally thousands of articles, on almost every cartridge ever fired, available for you to study. Study the bullet weight, type, alloy and amount of bearing surface, to powder speed and caliber relationship. When you approach the foggy regions, make sure you are using good quality cases, preferably new or at least documented once fired.
I rely on all the things you mentioned, case head expansion, extraction, primer and case head appearance. In addition I use recoil and muzzle blast. These items, all taken together, “may” warn you of impending doom. You must pay attention to what is happening with each and every shot. Consistent gripping, support and follow through with each shot will tell you a lot about that shot. This is not a rapid fire exercise. I use a quality Oehler chronograph. Read about and understand what the chronograph is trying to tell you, don’t just look for maximum velocity. Read, Record, Reload, Re-verify.
I hope the foregoing didn’t sound too much like a lecture. These process’s can be trying, fun and knowledge gaining, but proceed with caution.. Happy accurate shooting.
BTW, I agree, Clays is not a proper powder for use with the 454 Casull....G

Did not sound out of line at all tchepone. Quite the opposite....very well thought out helpful response. It's always interesting to learn how others approach these things rather you've been loading 40 days, 40 years, or just a mere 25 years as I have. Thank you for taking the time!

Sounds like I've got all my bases covered as well as one can. I was mainly curious as to how others approach evaluating their revolver loads and hoping I could learn a new trick or two. I agree with Clays being an odd mate for the .454 but the funny thing is it was considerably more accurate in these lighter .454 cast loads than many other more mainstream choices. In fact, the only thing that has bested those loads so far is TiteGroup. A couple powders I really expected to shine did down right pitiful. Perhaps the whole light boolit, light load .454 combo is an uphill battle. Definitely not what one thinks of when the Casull is mentioned, however I've put more rounds through the 'ol SRH in the last 6 months than I had in years and found it quite enjoyable to do so.

Larry Gibson, I'd also be interested in hearing a little about how you are able to actually test pressures. It sure would be interesting to be able to do so. I'd love to get a crack at seeing what the actual pressures are on these .454 loads with Clays.

[Mohillbilly]

If you really want to know , try here http://www.shootingsoftware.com/pressure.htm

[leftiye]

With all due respect to my esteemed colleagues. Basically, what we've said here is that if you avoid the plethora of cautions usually put forward by the high grounders, (and the cautions put forward here are very well founded) that pressure guestimation can't be done. And then we all proceed to do same every day, to do it sucessfully, not just suceeding in not getting hurt, but in suceeding to create safe loads that are accurate.

Barring pressure testing, as Larry has the equipment for, I think that you really can't target SAAMI max pressures accurately. I also think that that isn't necessary to do so before you can produce safe, accurate loads. First let me say that I've never before seen this subject pursued with less that top powders for a given cartridge. There is no real reason to push max pressures with a powder that won't ever produce max velocities.

That having been said, breech face imprinting only occurs at 60,000 psi plus. Magnum pistol pressures are in the area of 44,000 psi.. If your loads do this in most pistols, you're already in the Blind Retarded Chimpanzee realm. Pressure estimation in Rifles and pistols are different because of this. In other words all pressure in pistols occurs below any brass extrusion pressures. After all of this there are yet characteristics of brass expansion that can be seen. Brass (as measured in the web in front of the case head) will expand to conform fairly closely to a chamber at about .38 special prssures (20,000 psi.). It will plateau there (as measured) until enough pressure has been generated to lightly spring the chamber (way below sticking) and will show about .0005" more expansion at this point. This is also where scuffing starts to occur. This is in the mild magnum pistol area of pressure, also where nice safe loads that are relatively high performance and accurate can be found. From here until cases stick, or chambers bulge, you're pretty much flying blind. Here's where published loads with pressure data come into being needed.

Loads utilizing even more pressure than this are pretty rampant, but may not be safe. 22 grains of blue dot in my L frame .357 didn't show pressure signs that were alarming, nor did the cases stick. This has to be about 60,000 psi BTW. A good example of guns being built to handle more pressure than the cartridges should ever produce. There is a margin of safety built into guns, and in today's era of loads developed by lawyers more powder can be added, but tread carefully.

[Treeman]

Probably the best method of monitoring pressures with limited equipment is Ken Waters' method of measuring case expansion at the "pressure ring" You don't get anything in PSI but you can observe RELATIVE pressures and can tell when you are mild, near factory/normal and going above that.

[DougGuy]

I have reached the point where I look for accuracy over horsepower, and most of the loads drop out of the cylinder easy, no flattened primers, and I expect severe recoil when shooting the heavy boolits. I used to try and see how far I could go with it, but deemed that knowledge less important than finding the notch that works best for the gun, the game and the boolit.

[Larry Gibson]

leftiye

Got to ask; 22 gr Blue dot in a .357?

17.5 gr in a 44 magnum under a 250-K is a compressed load.........just wondering........

Also have you looked at the data I posted in the sticky on Blue Dot? If you do you'll notice that with Blue Dot the psi falls off drastically as the powder is compressed. I though this may be just a phenomenon with the .44 but it does the same in the .357 under 358156s. Whatever the 22 gr you got in the 357 under whatever bullet is probably a lot less psi than the 60,000 you think……..I would need the actual load data to test it though.

Larry Gibson

[44MAG#1]

Mr. Gibson. I would like to know what calibration ammo you use in calibrating your pressure equipment?
Do you use factory ammo? If you do do you get a sample of pressures with two or three different brands?
I just wonder how you do it to ensure that the pressures you are getting is the actual pressure or are you just comparing pressures based on figures that the testing equipment gives you and not necessarily the actual pressures based on a load you believe is giving the actual pressures you state?
I guess I would like to understand more about the protocol you use in your testing.
I have read about the Ohler personal ballistics lab testing apparatus and I think one must plug in barrel steel thickness and maybe type and a couple other things which I feel is potentionally frought with error depending on who is using it.
Am I wrong about the Ohler system?
Do you use a pressure gun like Hornady/Speer and calibration ammo?

[Old Caster]

Something that hasn't been mentioned and needs to be clarified is the use of a powder like Clays in a magnum type gun. Clays can be used in about any pistol load but don't even begin to expect that you can get anywhere near the same velocity as a slower powder. To get a maximum speed load, the powder has to be just the right burning speed for that particular cartridge and barrel length. The maximum load for Clays will be way down in speed from any powder that is slower than it but can be the same high pressure at the lower speed that the slower power is at higher speed. Clays would be fine to use if you want to shoot bullets around 750 fps but never take speed to mean pressure when comparing different powders. Whenever I am using pull down powders, I am very careful because I have no idea what speed it really is. After shooting some loads that are light even for fast pistol powder, I compare my velocities with manuals to get an idea of what speed the powder is. It won't be very long and I will find it similar to something else and will know what I can do. One caveat however is that some powder can spike in a hurry, so the phrase be careful can't be said, loud enough when doing this.

[sixshot]

Without having the correct pressure testing equiptment its pretty much impossible & I might add, dumb to exceed the loads listed in the reloading manuals, and referring to more than one manual is always a good choice.
Pressures in a straight walled case can be very deceiving, going by flattened primers or sticky cases isn't always the same. Tight or loose cylinder throats, tight or loose barrels, bullet hardness, seating depth, etc, all this plays into pressure & most of us have no correct way to safely measure it.
Ross Seyfried wrote a very interesting article a few years back about hot rodding the 45 Colt in strong sixguns (and 5 guns) he stated that early on he had no means to measure pressure but his cases were falling out of the cylinder & could be loaded several times, sounds safe enough!!! Later when the pressures were actually measured they were exceeding loads that were equal to Weatherby rifles!
Its much safer & makes more sense to just move to a big gun/caliber rather than straining a smaller one, a few feet of increased velocity just isn't worth the additional recoil & wear & tear on the gun & shooter, just saying!
After 45 years of taking big game with sixguns, mostly with loads under 1200 fps I can honestly say I've never recovered a bullet (cast) & never lost an animal & this includes everything from moose, elk & bear on down to small game. High velocity in sixguns is way over rated, forget maximum pressures & concentrate on maximum accuracy.

Dick

[Michael J. Spangler]

That pressure lab set up is pretty impressive.
On their web site they mention testing toward the top end of a load and getting to a point where more powder doesn't really equal more velocity.
I've heard mention of that before in threads on working up loads.

Is that a sign of maxing out a load at all? When you don't notice a return on
Velocity on the next .1 or .2 increase in powder the way you might have for the last few increase?

Thanks guys. This is something I want to know more about. I read about some crazy loads and wonder what is possible and what is just that, crazy.

I know the only thing I need to turn my 625 into a 460 rowland is another 1/16" of an inch of chamber. Though the bullet in the rowland is seated 1/16" deeper making it the same internal case capacity basically. (Some say the brass is thicker some have done tests and saw no difference)
So that revolver is made for 45 acp but can handle twice the pressure with 460 loads.

If I were working up a hot load in a two revolvers. One of very light construction and one of very heavy construction. would I be able to continue working up loads in both not noticing a difference in pressure signs in either but eventually blow up the poorly made firearm?
Are the pressure signs more dependent on case design, chamber finish, primer thickness etc than the actual construction of the firearm? What good would it be if you were well within pressure but the gun was poorly made and couldn't handle it, but you had now way to tell because the signs are dependent on other things than the actually response of the revolver to the pressure?

Is any of this making sense? I hope so.
Sorry I've been thinking of this a lot lately and wanted to see if some answers could be had.

Also I think I'm going to call Starline to see what they say about their AR brass vs their 460 Rowland brass strength wise. I wouldn't want to ream my chamber deeper if I could run some hot loads in the AR. Reaming could impair accuracy of the ACP and AR and make it impossible to shoot the ACP cases without the moon clips.

Alight that will be all. Thanks guys. I can always find the answers I need on this forum. There are some real smart members, not just a bunch of guys who shoot and reload a little in their spare time like I do.

[Larry Gibson]

44mag#1

Mr. Gibson. I would like to know what calibration ammo you use in calibrating your pressure equipment?

First of all “calibration” is not the correct term as that gives the impression the testing device is then “corrected” or set to zero or something like that. Not a problem as that is a common misconception. What is used is “reference ammunition” which is just a lot of factory ammunition that has been found to be of particular uniformity. That lot of ammunition is then pulled out of distribution and is sold, when approved, to ballistic labs. The labs use that ammunition in their test barrels. For example; SAAMI test .308W reference ammunition at 59,500 psi. Remington then shoots a 10 shot test through their .308W pressure barrel and get 57,750 psi, the difference being 1,750 psi. That is then the “off set” figure. Then when Remington tests a lot of it’s own .308W ammunition and get 56,850 psi they then add the offset figure and list the psi of that load as 58,600 psi for the SAAMI MAP. The psi and velocity will vary from test barrel to test barrel just as chronographed velocities vary barrel to barrel with the same loads. They will even vary a bit between test strings of the same lot from the same test barrel.

In the use of strain gauges which I use with the Oehler M43 they are “calibrated” after manufacture by the maker and a value given. That value for the strain gauge used is input into the data of the M43’s program.

Do you use factory ammo? If you do you get a sample of pressures with two or three different brands?

I just wonder how you do it to ensure that the pressures you are getting is the actual pressure or are you just comparing pressures based on figures that the testing equipment gives you and not necessarily the actual pressures based on a load you believe is giving the actual pressures you state?

I did use factory ammunition from of 5 different lots of .308W from Federal and Winchester. I got the “corrected” psi and the test conditions from the very helpful ballistic technicians from each. They also gave me the probable offset of psi between their minimum spec SAAMI barrel and what I could expect from my minimum spec commercial barrel. They also use strain gauge psi measure of their ammunition in commercial rifles. Thus when I tested the factory “reference ammunition” (2 different days with 10 shot tests of each lot) I found the psi the Oehler M43 recorded was very close to and within the parameters of Federal and Winchesters tests for each lot.

Additionally I have a large amount of a particular single lot of 7.62 ammunition and I use a particular minimum spec .308W test rifle for “verification”. Each time the M43 is set up for a test I run a test string from that lot of ammunition through that same test rifle. Since I take great care to ensure the set up is identical each time I’ve found the resulting test data to be within the normal variation between test strings.
I also use several different lots and types of factory and/or milsurp ammunition as a “reference” for load development with each new barrel. I a couple instances the data was not within expected parameters and usually a loose strain gauge was the cause. Once corrected the data was uniform.

I guess I would like to understand more about the protocol you use in your testing.

I have read about, studied, practiced the pressure testing methods used by ballisticians, discussed their technique with them, and that used by SAAMI. My “protocol” is to test as close to the same methodology as they use and to be as consistent test to test as possible. I also keep somewhat tedious records.

I have read about the Ohler personal ballistics lab testing apparatus and I think one must plug in barrel steel thickness and maybe type and a couple other things which I feel is potentionally frought with error depending on who is using it.
Am I wrong about the Ohler system?

You are correct about the Oehler M43 system. It requires quite a bit of information input regarding the test firearm (thickness of the chamber/barrel walls is one of them and it does differentiate by input between the type of barrel steel used). Complete information on the load and test conditions is also required.

Do you use a pressure gun like Hornady/Speer and calibration ammo?

If you are referring to a C.U.P. test receiver, no. Most major ammunition manufacturers use peizo/transducer test receivers for load development these days. They also use strain gauges on commercial firearms for additional checks with systems similar to the M43 but a little more sophisticated such as the much more expensive Oehler M83 (a much used test instrument by the ammunition industry). Dr. Oehler conducted a test of several peizo-transducers, a case mouth transducer and strain gauges with the M43 and M83 all connected to the same C.U.P. test receiver and barrel. Thus they all measured the psi/pressure curve (except the C.U.P. which just measures peak psi) of the same cartridge when fired. The test is extensive (I have a copy) and the results show the uniformity of measurement between the strain gauge measurements and the peizo-transducer measurements.

Larry Gibson

[44MAG#1]

Mr. Gibson:

I understand about the offset pressures etc.. But as the esteemed Mr. Felix of Cast Boolits forum fame once told me : "It's a pure terminology game to bring a concept into common agreement."
Websters gives this as a definition of calibrate: " 3: to standardize (as a measuring instrument) by determining the deviation from a standard so as to ascertain the proper correction factors " So I already understand one uses "reference" ammo to "calibrate" the test gun.
I appreciate your going into detail about the pressure testing method you use.
Now, If you would, how do you test the pressures of handgun ammo. I can understand measuring pressure in a Contender or Encore as the strain guages will be more easily put on the chamber area but how does one do that on a revolver?
Do you have any pressure tests of ammo from Remington, Winchester and Federal on the 44 mag you could give out as opposed to the likes of some of the people like Buffalo Bore etc?
Also Speer says that the SAAMI spec pressure of the 45/70 is 28000 cup 28000 psi as both are the same in the 45/70.
Does this hold true at higher pressures on up to the 40000 cup/psi pressure ranges or do they switch around?
I ask this because companies like Garrett and Buffalo Bore load their ammo to higher pressures than the SAAMI specs with (here I go again probably in error) Buffalo Bore going up to 42-43000 psi.
I think one pressure testing their own ammo is an interesting thing but at times I scratch my head at the info given out by testers such as Speer, Hornady etc..

[Mohillbilly]

In pistol/revolver cartridges I use Corbon and shoot them in my rifles with the pressure test equipment . I use that results as a red line . I then make some reloads and shoot them in both to see where I am at .

[leftiye]

Probably the best method of monitoring pressures with limited equipment is Ken Waters' method of measuring case expansion at the "pressure ring" You don't get anything in PSI but you can observe RELATIVE pressures and can tell when you are mild, near factory/normal and going above that.

That is basically the same process as I was trying to elucidate.

[Starvnhuntr]

I load a 300gr. semi wadcutter gas check boolit from a lee mold for my .454 cassull with 24 gr. of IMR-4227. I am shooting it in a freedom arms 10 in. shoots like a heavy .44 mag.

[tek4260]

To the OP,

There are too many variables for the average, and above average handloader to try to gauge pressure by looking at cases, extraction, primers, ect. Everything from smoothness of chambers, size of chamber, headspace, can muddy the signs of pressure. The only way I feel safe running a revolver to the max is using H110. Simply mark your case to show the seating depth of your bullet and fill the case to that point. That is my max load in strong revolvers. Trying to get more with faster powders is dangerous as they can spike with just a small change in the charge.

There is a reason H110/296/LilGun are the "go to" powders for maximum loads.

Now, if you really want to be brave in a somewhat educated manner you could try maxing it out with something like H110 at 100% load density. If you want more, look at the powder burn rate charts that list powders in order of their relative burn rate and choose the next fastest powder. Reduce your loads a bit and start working up again with that "next fastest powder". If you get to 100% load density and aren't happy, use the next fastest powder and start over. Sounds good in theory anyway.

[Ed K]

In my Lyman manual it is stated many times: "although these loads were not pressure tested, they were perfectly safe in the test firearm". Alright, how do they determine that I would like to know...

[cbrick]

Never have I found the hottest possible load in any given combination of powder/boolit to be the most accurate. I start low and work up while shooting 150 meter groups from the bench over the chrono. The groups will shrink as you approach the ideal for your load/revolver and usually just a bit more and groups degrade even though usually published data says you can go hotter.

I never try to squeeze the last few fps out of a load, I let the target tell me that's all this gun/powder/boolit will shoot well and that could well be different for each gun/combo. You have to accuracy test to get the answer to your question - "Max loads in revolver". At least for me it's all about the accuracy and little to nothing about a meaningless few extra fps.

Mr Target is very smart and he will tell you if you ask him.

Rick

[44man]

In my Lyman manual it is stated many times: "although these loads were not pressure tested, they were perfectly safe in the test firearm". Alright, how do they determine that I would like to know...
The guns did not blow up!
The knowledge from many here show how difficult it is to gauge pressures without test equipment.
Some will use a chronograph to judge by trying to reach book velocities but every gun is different.
I have a great fear of pressures. It took me a month before I shot my 45-70 revolver. I tried the touted 4198 and it was doing well. I weighed each charge but one shot went over 1800 fps and stuck a case. The powder was not a match for my gun so I dumped it. For some reason the powder spiked. Just because the rest of the shots were in limits and were accurate did not mean all is good.
The revolver is so different, it has a pressure vent at the gap and can save you from an S.E.E. event. Did I have a boolit jump tension and crimp from a delayed ignition?

[Larry Gibson]

44Mag#1

I understand about the offset pressures etc.. But as the esteemed Mr. Felix of Cast Boolits forum fame once told me : "It's a pure terminology game to bring a concept into common agreement."
Websters gives this as a definition of calibrate: " 3: to standardize (as a measuring instrument) by determining the deviation from a standard so as to ascertain the proper correction factors " So I already understand one uses "reference" ammo to "calibrate" the test gun.

I disagree with neither you, Felix or Webster. I gave specific example concerning the misconception of “calibration”. You asked if I “calibrated” my pressure equipment. I answered that question. If you wanted to know if I used an offset measurement obtained with “calibration ammo” perhaps a more concise question would have got the same answer. No I do not “calibrate” the pressure equipment by adjusting it as one does a micrometer or caliper (my answer) which is what I mistook you to mean. To adjust the measuring instruments back to “zero” would have also been a “proper correction”. And yes many mistakenly do think that is what is done when the improper term of “calibration ammo” is used. May not have been what you meant but it is what I took it for based on answering that very question many times. Yes I do use an offset with reference ammunition (the answer you were looking for). As we see, not using the correct terminology easily leads to misunderstandings and perhaps it is my bad that I did not seek clarification of your question before I answered. I am of the opinion that when we are talking the technical aspects of this hobby we should use the correct terminology regardless of Mr. Webster’s broad definition, just my opinion of course.

I appreciate your going into detail about the pressure testing method you use.
Now, If you would, how do you test the pressures of handgun ammo. I can understand measuring pressure in a Contender or Encore as the strain guages will be more easily put on the chamber area but how does one do that on a revolver?

The ammunition industry does not use revolvers either for their psi tests. Some still do and some standard barrels that are “vented” in front of the chambers to simulate the barrel cylinder gap of revolvers. I use Contender barrels to pressure test numerous cartridges, particularly handgun cartridges. That gives very close to the same psi measurements as with industry test barrels. Contender chambers are more often “tighter” and there is no free bore as in revolver throats and no barrel cylinder gap. That means the psi’s of a given load will be less in the revolver.....a built in safety factor if you will.

A strain gauge can be attached over a cylinder’s chamber and used IF there is sufficient clearance between the cylinder and top strap for the attached gauge and wires. The cylinder must be opened after each shot (if a DA and the cylinder removed for a SA revolver) to load another round for testing; pretty much a PITA. Attaching the strain gauge is also permanent and if removed for further use the cylinder is “scarred” or will need to be refinished. Additionally, since the metal is not even around a revolver chamber the psi measurement will generally not be accurate as “psi” and reference ammunition will have to be used for the offset.

Do you have any pressure tests of ammo from Remington, Winchester and Federal on the 44 mag you could give out as opposed to the likes of some of the people like Buffalo Bore etc?

Yes, I have tested some MagTech, Winchester, Remington and Hornady factory 44 Magnum ammunition.

Also Speer says that the SAAMI spec pressure of the 45/70 is 28000 cup 28000 psi as both are the same in the 45/70.
Does this hold true at higher pressures on up to the 40000 cup/psi pressure ranges or do they switch around?

Again a matter of semantics; the SAAMI MAP is listed as both 28,000 for C.U.P. and peizo-transducer for the 45-70 cartridge. There are other SAAMI “spec”’s such as the MPLM and MPSM which are also determining factors as to whether a load is deemed “safe” or not. An additional note regarding SAAMI “spec”’s (MAPs); many mistakenly believe all factory cartridges are loaded to the SAAMI MAP. Fact is most are not and are loaded under the SAAMI MAP.

As I have mentioned, as others have also, there is no valid conversion or comparison of C.U.P. psi’s into peizo-transducer psi’s. There is a very narrow band in some cartridges where the “psi” of both overlap and are the same. The 45-70 is one of those few cartridges.

I ask this because companies like Garrett and Buffalo Bore load their ammo to higher pressures than the SAAMI specs with (here I go again probably in error) Buffalo Bore going up to 42-43000 psi.

The SAAMI MAP for the 45-70 is based on it’s use in older BP firearms such as Trapdoors. Buffalo Bore and Garret’s cartridges are loaded for use in modern firearms such as the Marlin lever actions, Ruger single shots and rifles built on Siamese Mauser actions. I do believe there is admonishment in the literature and on the boxes of ammunition that the ammunition is for use in modern guns and not in older BP firearms.


I think one pressure testing their own ammo is an interesting thing but at times I scratch my head at the info given out by testers such as Speer, Hornady etc..

As I’m sure you are aware the 45 Colt, 44-40 and several other cartridges, including the 45-70, are loaded to different “levels” based on the strength of the firearms they are used in. Sometimes we must read the “fine print” to understand what is said/printed reading those loads. Also we must understand that when talking to those “testers” we must understand they are ballisticians who use the correct terminology. Not being critical but with such the specific and correct terminology instead of generalized terms helps us to better understand the more technical side.

Larry Gibson

[Larry Gibson]

In pistol/revolver cartridges I use Corbon and shoot them in my rifles with the pressure test equipment . I use that results as a red line . I then make some reloads and shoot them in both to see where I am at .

If Corbon loads the cartridges that is a very good use of "reference ammunition" as my limited testing of Corbon ammunition is that they are most often pretty close to the SAAMI MAP.

Larry Gibson

[Larry Gibson]

In my Lyman manual it is stated many times: "although these loads were not pressure tested, they were perfectly safe in the test firearm". Alright, how do they determine that I would like to know...

The technicians/ballisticians have a wealth of knowledge and experience loading cartridges. They develop safe loads watching for all the pressure signs (usually published in the manual they are developing the data for) plus measuring case web expansion and comparing and understanding the expected velocity (including the ES and SD of 10 shot test strings) with a given bullet/powder out of given cartridge. Also as mentioned; "the gun didn't blow up"!

They've probably "gone a bridge too far" and have learned when to back off. Wouldn't you prefer to learn from their mistakes and not take a risk on damaging your firearm or yourself? I know I have learned that lesson........the hard way.........and prefer to admonish others to learn it the easy way.........

Larry Gibson

[44MAG#1]

" You asked if I “calibrated” my pressure equipment. I answered that question. If you wanted to know if I used an offset measurement obtained with “calibration ammo” perhaps a more concise question would have got the same answer."
I am reminded of the episode of Little House On The Pararie where Mrs Olsen was having trouble with her stomach and she went to the doctor. He examined her and gave her a diagnosis. The name of the illness had her thinking she had some rare disease and she paraded around town leting people know the name of the disease she had.
The doctor later told her the name of the disease was a medical term for gas.
I admit I am a slow witted individual with a desire to use an uncomplicated process to comunicate with people due to many being like me which is simple minded. That doesn't mean I don't know it just means that to scientist and the highly educated it is common place to use very accurate methods of speaking.
"The SAAMI MAP for the 45-70 is based on it’s use in older BP firearms such as Trapdoors. Buffalo Bore and Garret’s cartridges are loaded for use in modern firearms such as the Marlin lever actions, Ruger single shots and rifles built on Siamese Mauser actions. I do believe there is admonishment in the literature and on the boxes of ammunition that the ammunition is for use in modern guns and not in older BP firearms. "
I think we misunderstood each other even here. I have Garrett, Buffalo Bore, Winchester and Rem factory 45/70's.
I was asking if the pressures at the upper levels were just like the SAAMI spec pressures when at the 28000 PSI 28000 cup levels being the same or do they swap around with the cup and psi being positionally change such as the 30/06 which is 50000 cup or 60000 psi according to SAAMI. I know the same "reference" ammo is used to ascertain the offset pressures of both measuring devices. If I see data for the 45/70 and it is listed at 40000 psi is that just like 40000 cup or is it not.
Just like if it is listed at 18000 psi is that the level in cups also?
Also I am not asking if there is a correlation between cups and psi as that is an old argument that some will never let die. There is to a degree as I stated before that the same "reference" ammo is used to get the correction factor for both types of devices. Cup gives peak but Piezo gives start pressure with peak and the whole works along with time of duration etc. that can be reviewed by said ballistician other than just measuring a copper slug and looking at the tarage table provided by the supplier of the copper cylinders and writing that down.
I am sure that by my use of some terms I appear wrong and more than likely are but that is nothing new with me.
Oh yes, I do appreciate your infomation. It is well received.

[Ed K]

The technicians/ballisticians have a wealth of knowledge and experience loading cartridges. They develop safe loads watching for all the pressure signs...

And those are???

We hear over and over that sticky extraction, flattened primers, expansion rings, and the like are not reliable. Then Lyman states that they blow off pressure testing on a good number of data sets with the claim that the loads are "perfectly safe". Something doesn't add up.

My entire life I've been scolded from engineers to electricians that I shouldn't ever attempt something. Then I do the deep dive on the topic only to find out the engineers aren't really running the numbers for an optimal solution but using a one-size-fits-most "rule of thumb". My electrician tells me to stay away from circuits lest I burn the house down killing the family - he tells me the same day he drills the snot out of an 52' engineered beam 22' above my family's living room. Had to get a crane in to replace the beam setting the whole project back. What if I didn't find it? Well at least the family would have been killed by a licensed and insured professional!

[bbailey7821]

Ed, you're gonna ...

[44man]

I had a part time job as chief sawer to make roof trusses. I would saw one truss and lay it out on the press table. I used the cut order from the engineers book that the boss gave me. Some angles were wrong and nail plates too small. I would correct cuts and increase the size of nail plates. The boss came out and seen the plates I used. He got upset and said to use the smaller ones.
When they were loading the trusses on the truck, they were falling apart so my friend had to hammer in new plates with a HAMMER. That doubled the price of plates.
Then he gave me the wrong cut order for hundreds of trusses for a large motel. I found the problem, fixed it and made all the trusses. I went to the office the next day and told him he gave me the wrong info, he turned white. I told him we fixed it and saved him many thousands of dollars, I think it was $14,000. He gave me a quarter dollar raise so I quit.
I am a simple person but do not believe what is on paper about loading some things. I hate math but get along.
True CUP and PSI might cross but the difference can NOT be compared in any way.
If the gun maker says to not go over 30,000 psi and all books are in CUP, where the heck are you? You are in the same place I was with a stack of 2x6 lumber. I could have bankrupt the owner and you can blow up your gun.
There is simple like me and common sense and smart as all get out with no common sense at all.
Don't fool with pressure.

[44MAG#1]

44man said:
"True CUP and PSI might cross but the difference can NOT be compared in any way. "
I don't know any reloader with any experience that says they can as far as a formulation for figureing cup from psi or vice versa.
But if the SAAMI specs on a load is 50,000 CUP and the loading data is in CUP's then what they list as max is max in that lab test.
If the test is done in PSI and the SAAMI specs on the load is 60, 000 PSI then that is maximum.
Where the problem is is where you have some illogical thinking guy says my book list cup's and the load is 50,000cup and I know the limit is figured in another book at 60000 psi so I can bump up the load to 60000. You can't the book in CUP is MAP and the book in PSI is MAP. The 30/06 comes to mind on this. Also the 458 Win Mag 53000 cup/63000psi. Many more too.

"Don't fool with pressure"

If you reload you HAVE to fool with pressure. It is when one gets into unknown territory that pressure becomes a problem. Also the lack of pressure can become a problem too. Remember your written work on the 454 Casull and dropping the charge down too low. Most of us that have used the 454 knows that 23 to 23.5 gr H110/W296 is too low even with 330 <> grain bullet no matter what Hodgdons says.

[44man]

You stated it correctly, unknown territory!
Yes, it relates to too low for a powder too and you have a good handle on it.
I have fear, real fear to tread at places willy-nilly. I have to go by the books and if a max load is 200 fps less then the book, it is fine with me. To hunt for the velocity is insane.
I read what you and Larry say and have to say everyone should pay attention.

[Ed K]

I'm going to write a follow up post before anyone gets the idea I'm either looking to pick a fight or to take a cartridge into territory it doesn't belong. I've been reloading for 25 years - without incident I must add. It is not my intent to wring as much power as possible out of a round. What makes me curious is how someone can determine what loading is/isn't safe without pressure testing - that's all. It's got to be something that can be defined, put into words, backed up by a set of variables known to be within limits, etc. It can't be some feel good, horse whisperer, Zen, kinda thing that serves as the basis for our safety.

Seems to me my comments are on topic with the OP's "Finding Max Loads in Revolvers" question.

[Larry Gibson]

44MAG#1

"The SAAMI MAP for the 45-70 is based on it’s use in older BP firearms such as Trapdoors. Buffalo Bore and Garret’s cartridges are loaded for use in modern firearms such as the Marlin lever actions, Ruger single shots and rifles built on Siamese Mauser actions. I do believe there is admonishment in the literature and on the boxes of ammunition that the ammunition is for use in modern guns and not in older BP firearms. "

I think we misunderstood each other even here. I have Garrett, Buffalo Bore, Winchester and Rem factory 45/70's. I was asking if the pressures at the upper levels were just like the SAAMI spec pressures when at the 28000 PSI 28000 cup levels being the same or do they swap around with the cup and psi being positionally change such as the 30/06 which is 50000 cup or 60000 psi according to SAAMI.

You understand correctly. When you see the same C.U.P. & peizo-transducer psi for the 45-70 they are essentially are saying it is the same psi.

I know the same "reference" ammo is used to ascertain the offset pressures of both measuring devices. If I see data for the 45/70 and it is listed at 40000 psi is that just like 40000 cup or is it not.

No, it is not. As I mentioned in the previous post there is a narrow band of psi IN A FEW CARTRIDGES that will have both the same C.U.P. and peizo-transducer psi’s. Again it falls in a narrow band and applies only to a few cartridges which is where some have tried to come up with a formula for correlation. If measured via peizo-transducer or strain gauges 40,000 psi does not correlate to a 40,000 C.U.P measurement.

Just like if it is listed at 18000 psi is that the level in cups also?

You have to read the information regarding how the “psi” was measured. If measured via peizo-transducer or strain gauge it is not the same psi as 18,000 C.U.P.

Also I am not asking if there is a correlation between cups and psi as that is an old argument that some will never let die. There is to a degree as I stated before that the same "reference" ammo is used to get the correction factor for both types of devices. Cup gives peak but Piezo gives start pressure with peak and the whole works along with time of duration etc. that can be reviewed by said ballistician other than just measuring a copper slug and looking at the tarage table provided by the supplier of the copper cylinders and writing that down.
I am sure that by my use of some terms I appear wrong and more than likely are but that is nothing new with me.

Ballisticians are finding out that the “peak psi” obtained via C.U.P. measurement of the crushed copper cylinder is misleading and many times not reflective of the actual peak pressure. We know for instance that when measuring BHN the indentation must be made by applying a set pressure for a given time. The C.U.P. does not take into consideration the dwell time during the crush. They have discovered by observing the time/pressure curve (trace) that many times a C.U.P. measurement is not measuring the actual peak psi. This is another reason the peizo-transducer and strain gauge methods of measurement is more commonly used these days. As you mention the ballistician gets a much better and more complete picture of the internal ballistics.

Oh yes, I do appreciate your information. It is well received.

I am enjoying the discussion and conversation.

Larry Gibson

[Larry Gibson]

Ed K

Most all of the better commercial reloading manuals have a section up front detailing "pressure signs", they are what the ballisticians/technicians use to develop loads when they are developing loads in actual firearms. More of the industry is using strain gauges with such loads now days and I expect we won't see many loads developed w/o such tecknology in future reloading manuals.

Bottom line is the information about pressure signs and how to observe/measure them is all we have in the absence of actual pressure measuring equipment.

Larry Gibson

[44man]

This is a good thread and I agree with Larry about the copper crusher. Some powders reach peak before the copper and others peak beyond it. The only time it is close is when a powder peaks right at the crusher position.
It is outdated and all they had. Like the pendulum to determine velocity. Bullet construction alone can make the pendulum react different. Dwell time!

[W.R.Buchanan]

Ultramag and others. This has been a stimulating discussion, and whereas I understand the OP's goal, I don't not understand why you are persuing it.

Accuracy is not necessarily contingent on highest velocity. IN most cases it is counterproductive. The only benefit of a higher velocity is a flatter trajectory, which in a long range rifle could be of some use. However in a revolver that you are not going to shoot beyond 100 yards on a good day, exactly what benefit will a midrange elevation of 6" accomplish over a midrange of 4" ?

Being able to shoot the gun and connect with the target far outweighs the increased velocity of the projectile . A miss with a 257 Weatherby does exactly the same as a miss from a .22.

A .44cal 250gr SWC lead boolit at 900fps (midrange .44 Spec) will go clean thru an elk sized animal. It will poke a 7/16" dia hole thru just as if a piece of steel rod was driven thru.

A .454 Casull with a 250 gr boolit at 1500 fps is going to do pretty much the exact same thing, except the hole will be 15/32" instead of 7/16". And the likelyhood of you actually making two consecutive hits with that combination are slim at best.

Flirting with max and max + loadings is best left to those with not only the technical expertise but the equipment to monitor what they are doing. The vast majority of those types work for Powder or Ammunition companies already and it's pretty much all they do.

My real point here is that no matter what your intentions are with this quest, I feel that you are addressing the wrong target.

I would suggest that you find a load that you can shoot well, and alot,,, and practice with that rather than trying to wring out the last few rpm's from your gun. The fact that you are shooting a .454 Casull pretty much settles the power factor arguement as any load from that gun is going to be more than powerful enough for just about anything you're gonna shoot.

Your ultimate target will not know the difference, and you might live long enough to actually shoot it.

Randy

[cbrick]

However in a revolver that you are not going to shoot beyond 100 yards on a good day, exactly what benefit will a midrange elevation of 6" accomplish over a midrange of 4"? Randy

Excuse me? A mere 100 yards? Just getting warmed up at 100, that's only half way there. :mrgreen:

Rick

[GLynn41]

good discussion and I would only add Speer sent me data for a .41 that turned to beway over what the powder maker says- not picking on Speer but it has happened to me with a Speer book load in a .454 and it was way over --since I tend to work up close to book top loads -which for me in rifle or handgun is a grain or 1.5 below max- and it was a Ruger super .454 -one round told the story way over blast, recoil and a very stuck hull Larrys comment about the new data is a good one -I have an old Lyman cast bullet manuel that goes very high with the old 2400 and a .41 220 keith --

[35 Whelen]

I asked this same question awhile back after acquiring a couple of Uberti .44 Special's and Flat Top .44 Special. I pretty much got the same results you have; no really concrete answers, but plenty of bickering among the posters and plenty of folks telling me what NOT to do. It's kind of funny...folks told me every firearm is different and that no two pistols would handle the same load alike. Then these same folks told me not to worry about reading pressure, but instead to stick with published load data. Now, I'm almost positive that the fellas who produced the published load data did NOT use my handguns to develop this data...you see where this is going, don't you?[smilie=1:

Like you, ultramag, I like to try new things and stray from the norm. With the recent shortage in components, and especially powder, I've been experimenting with powders that aren't advertised for use in handguns; specifically e3, 20/28, and Pro Reach. e3 is a very fast burning powder, even more so than B'Eye, so I started out with light B'eye-weight loads and worked up from there. I did not seek to "max out" the powder, rather when velocities with a given bullet weight approached the levels of a slower burning powder, say 20/28 or Unique (which by the way are for all practical purposes identical in performance) in the case of e3, I stopped there. Likewise when developing loads for 20/28, when the velocities began approaching those I'd gotten with light-ish Blue Dot loads, I stopped there.

I've loaded some pretty salty loads in my Blackhawk .44 Special and my Security Six .357, but never really saw any physical signs that I could positively attribute to excessive pressure. What HAS always kept me in line is a chronograph. I remember reading in Handloader magazine once that when developing loads that velocity should increase proportionately with powder charges and when velocities cease to increase as such, you're approaching maximum pressure. (If anyone disagrees with that statement, don't flame me, rather send a letter to the publisher of the magazine)

35W

[Larry Gibson]

I remember reading in Handloader magazine once that when developing loads that velocity should increase proportionately with powder charges and when velocities cease to increase as such, you're approaching maximum pressure. (If anyone disagrees with that statement, don't flame me, rather send a letter to the publisher of the magazine)

My guess is (because I recall reading the same or similar article) is that if one reads the "fine print" we'd find the reference is to developing loads in rifles. I can say unequivecally, since I have measured a lot of pressures in handgun cartridges, that the above statement does not apply for several reasons; with the exception some of the specilized handgun cartridges in specialized revolvers for them most all handgun cartridges can easily be loaded way above the structural limits of the handguns made for them and the velocity will increase linearly as the psi increases. By the time the velocity does not increase with an appropriate powder charge most often the psi will be way too high for most every revolver. Also most all revolver or other handgun cartridges are straight sided cases which gives them a very low expansion ratio. Some times with certain powders the powder is being blown down the barrel and out before it has a chance to burn efficiently. Thus the velocity gain will cease and the psi may not increase as well. It may in fact decrease, refer to my test with Blue Dot in the .44 Magnum and you will see just that.

I'm not telling 35 Whelen what to do or not to do nor am I bickering with him nor anyone else. Disagreement or pointing out the pitfalls of pushing the maximum pressure envelope as a safety note isn't "bickering" in my humble opinion. With revolvers, when developing loads to a "maximum" level, unless one is very knowledgeable and/or has appropriate testing equipment it is prudent to stay within reliable published load data from the major industry sources. That 35 Whelen feels comfortable and confident in his own ability to go above maximum loads or experiment with non listed powders for a cartridge is fine with me as I do that also. However, there are a lot of very new and inexperienced reloaders on this forum; to lead them down a path to "try new things and stray from the norm", even with the shortage of componants is not prudent, again, in my humble opinion. For most reloaders w/o the knowledge, experience and testing equipment to stay within industry load data to be safe is a suggestion, not "bickering".

For those who have the knowledge, experience and testing equipment who want to "try new things and stray from the norm" then have at it. Kindly don't blame the revolver manufacturer if things don't go as you think they should.........

Larry Gibson

[W.R.Buchanan]

I read the same article in Handloader and it was written by Terry Weiland. It was also about as badly written as any super technical article I have ever read. I read it several times and I found that he basically belabored a point that should be fairly obvious, however in doing so all he created was gross confusion. IN short he really didn't understand what he was talking about.

Here's how I know that.

My basic operating perameter for judging usefulness of written material, or for that matter verbal information, is the clear and concise conveyance of the subject material.

If you don't understand it the first time thru then chances are you have misunderstood words in the text. IN order to get the complete picture of what the guy is talking about, you must understand every word in the context it is given.

When the author starts bandying around many technical terms and the text still doesn't make sense, even after you clear all the technical terms and understand their meanings, then all that is left is to question the source. IE: He's probably full of ship!

When you start talking about subjects as complex as ballistics and pressure burn ratio, and such like that, you are entering the realm of very technical subjects which if not fully understood can result in severe damage to you or others.

NO ONE !!! I have ever known, or even heard of, has the ability to grasp a subject as complex as what we are exploring here with just one read thru of an article. An article scattered full of highly technical terms which very few people understand, is not well served by being put forth by someone who does not have an exceptional command of the subject. The fact that there was not even a glossary accompanying that article pretty much seals it's fate.

IN my book the author of that article didn't really undertand the subject well enough, because if he did he could have explained the subject in plain english so that anyone who read it would understand the subject when done. You might have to read it several times but you could get there. This article was not like that! But it was published in a National Magazine.

Dave Scovill editor of Rifle/Handloader Magazine took about 40 minutes at the SHOT Show two years ago to explain Pressure Burn Ratio to me. Pressure Burn Ratio essentially is why certain powders work well in some cartridges and don't work well in others. When he got done I explained it back to him, to his satisfaction! He never once used a technical term beyond the normal vocabulary of the average competant reloader. Whereas I donot understand all of the minutia associated with this subject, I do understand the overall concept, which is all I really need. I can be safe. He could have written the article in question and everyone would have understood it.

When someone starts talking technical to me and they largely don't make any sense, I pretty much conclude that they are FOS... And when I talk technical to someone, I'm pretty serious about making sure that they don't Yawn during my converstation with them, and if they do I find out what they didn't understand and fix it. I frequently ask, "does this make sense?" simply because it is completely pointless to go beyond the point where somone doesn't understand what you are talking about.

I just finished a presentation on what techniques I use to refurbish equipment for the US Navy,,, to the Germans! I can safely say that all but one understood everything I said, and the one that didn't,,, got the subject translated, as I spoke the second time thru until he understood as well. As a result these people who have many machine shops to choose from in Germany, are buying from me,,, here! And believe me the job is worth doing!

It's all about knowing what you're talking about. If you do, you can explain it to someone else and they will understand as well. Simple as that!

If you don't,,,They won't,,,, and you are FOS! Simple as that!

Randy

[jonp]

leftiye

Got to ask; 22 gr Blue dot in a .357?

17.5 gr in a 44 magnum under a 250-K is a compressed load.........just wondering........

Also have you looked at the data I posted in the sticky on Blue Dot? If you do you'll notice that with Blue Dot the psi falls off drastically as the powder is compressed. I though this may be just a phenomenon with the .44 but it does the same in the .357 under 358156s. Whatever the 22 gr you got in the 357 under whatever bullet is probably a lot less psi than the 60,000 you think……..I would need the actual load data to test it though.

Larry Gibson
I'm still waiting on the interesting answer to the 22gr of Blue Dot in a 357Mag. That is so far beyond anything I can find that I'm wondering if it is a typing error.

[Larry Gibson]

Case in point:

Some years back when I was still young and dumb and prone to “push the envelope” before I obtained the Oehler M43 to actually measure psi’s I decided to up the Blue Dot loads under the Hornady 125 XTFP. The industry max loads hovered between 14.3 and 14.7 gr in the manuals under the various makes of 125 JHP/SPs. I was developing loads in my 6” barrel Ruger Security Six. I had used 14 gr of Blue Dot under the Winchester 125 JHP some years before in a 4 5/8” barreled Ruger BH The cases had literally fallen out of the chambers with that load. I felt with the velocity the BH got the psi’s were minimal and performance could be enhanced with just a tudge more powder. However, I had learned to be a bit prudent by then so working up a load for the Security Six was done. I had a brick (500 bullets) of the XTFPs so it seemed like the thing to do.

I used an Oehler M35P chronograph to track velocities and the SD/ES of each load. I was also well versed in the manual listed “pressure signs” for working up loads in revolvers. I use W-W cases with WSP primers. Velocities are with the center screen at 15’. The XTFPs were seated to the canelure and a hard roll crimp applied in a 4th step. I started at 14 gr and worked up to 16.4 gr (that was the max charge I had seen in one reference)and was slightly compressed. Ten shot test strings for each charge were used. The results were;

Charge/velocity/fps gain over previous charge

14/1497
14.5/1536/39
15/1577/41
15.5/1620/43
16/1659/39
16.4/1690/31

As you can see the increase in fps is consistent. There were no pressure signs and the cases easily were extracted and ejected with a thumb push on the ejector rod. I’ve shot close to 400 of the 16.4 loads with nary a sign of pressure. Accuracy is excellent and they kill rock chucks, coyote’s and deer like lightning. I was going along fat dumb and happy with that load w/o a concern. Then a friend tried it in an L frame S&W. The cases had to be pushed out with a rod. He swore he hadn’t screwed up the load but I questioned that. Then along came the M43 Oehler and I was able to pressure test .357 ammunition with my Contender Barrel. The following factory ammunition produced the following peak psi’s in 10 shot test strings;

Winchester 125 JHP/30,400
Winchester 158 Lubaloy/32,500
Remington 110 JHP/28,500
Remington 158 LSWC/28,500
Federal 110 JHP/24,700
Federal 158 LSWC/30,300
S&W 158 LSWC/32,300

As we see all the factory ammunition was under the SAAMI MAP of 35,000 psi. Then I tested the Blue Dot 16.4 gr/125 Hornady XTFP load. The peak psi was 43,900!!!! That was considerably over any factory .357 Ammunition and considerably higher than the SAAMI MAP for that cartridge. That load certainly “seemed” safe and exhibited no pressure signs in the Ruger Security Six which is hell for stout. It is no wonder it tied up the L frame S&W though. No, I haven’t backed off on the Blue Dot loads I’ve already loaded (less than 50 left) but I heavily mark them as for use in the Ruger and Contender only and will only use them for hunting in cooler times of the year. I am then backing the load down until the MAP runs right at 34 – 35,000 psi though for future use. So I do “push the envelope” still but only when I know what’s happening as I’ve the equipment to measure it now. On the other hand I do not recommend it simply because components are currently in short supply or when the reloader doesn’t have the experience and knowledge.

Larry Gibson

[W.R.Buchanan]

Larry: Your last two sentences pretty much tell the story.

Randy

[44man]

I don't PUSH the envelope but some of my revolver loads are a small amount over book max, maybe 1/2 gr, because that is where accuracy for the boolit is. Most are under book because of accuracy.
Working loads will always see groups get smaller and then open again so why go for more? BACK DOWN.
I have seen velocity go down with test loads too much but pressure does NOT GO DOWN because the velocity is lower. There is no comparison between velocity and pressure that is safe to search for. Put the chronograph away.
Larry is correct that one gun will shrug off what can ruin another. But you do not know what pressure you are pushing.
A side note. I have seen loads in Handloader that scare me. Gun writers today do not have smarts.
I will stay with our folks here.
Work your gun for accuracy and end it. Stop looking for speed. Just because a modern revolver can work at Weatherby pressures does not mean you have to go there.
The secret to accuracy is stability to twist within safe loads.

[leftiye]

I'm still waiting on the interesting answer to the 22gr of Blue Dot in a 357Mag. That is so far beyond anything I can find that I'm wondering if it is a typing error.

Answer? There is no answer. I did it by accident (3 times). No typo. That I still have a good revolver and right hand is the amazing part.

There's been so much carp thrown about on this thread that I doubt anyone has benefited in knowing how to work up pressures and produce safe hot loads. Ironically most of what has been said was correct, but overall, I think it has just confused those who needed the info. Too bad that we can't keep our mouths shut if we don't have anything to say that is a contribution.

44man has what is probly the key. Maximum velocity always comes with a loss of accuracy. Killing power isn't any better than the most accurate loads. You can stop at best accuracy with most powders and rest assured that pressures are near max..