Dealing with anomalies in load data

[Blackwater]

I think we've all met the problem of discrepancies in load data at some time, maybe with a particular powder in a particular bullet, be it handgun or rifle, cast or jacketed. I'm dealing with this now in a .35/.303 imp. I got from our own Goodsteel here. The cast loads won't be a big problem, and having to test loads isn't anything but a pleasure and an oppotunity to learn more about this very nice gun, an old #4 Brit Enfield.

I want to keep my loads down in the 44K CUP range in deference to the old soldier's action. Want it to last a long time, and not develop problems. I've been perusing .358 Win. data, and it varied quite a bit from manual to manual. Some manuals list a starting load for some bullets that is equal to or exceeds slightly the min. load in another. All I've been able to figure to do is to try the lower listed data first, and if my chronograph's indicated velocity seems to indicate it appropriate, work upwards cautiously, always watching primer appearance as I go, normally.

With the old #4 action, primers won't be much of a help since they're only useful when approaching max. loads in stronger actions. At the levels of pressure that are good in the #4, primers don't really tell me much, so I'm back to gauging pressures simply by watching velocities on my chrono. What do you folks do when in a similar position, and need to use another caliber's data as a guide, and need to be cautious about the pressures you are getting?

Without a pressure gun, we're really feeling our way in the dark. Modern piezo pressure guns tell a LOT more than the old copper crusher tests gave us, but it seems to have generated an even wider array of test results than the old copper crusher results ever did. This may well be a good thing, but it certainly puts us in a more inquisitive position in the process. How do you guys deal with this type situation?

[Tatume]

Old guns can be enjoyed without maximum velocities. Even if you want to hunt with the gun, there really is no reason to push muzzle velocity to the limit. It shouldn't be difficult at all to safely achieve 2100 fps with your cartridge and 200 grain jacketed bullets. With the Sierra 200 grain round nosed bullet that will give a +/- 2" trajectory past 150 yards. If more is needed, there are other guns to use.

[vzerone]

A good many of the differences between loading manuals (talking about the ones put out by the bullet manufacturers) is the data is for their bullet. There's no need to explain the differences between the brands as you all know them. Another difference their particular testing equipment which I'm sure differs from tester to tester. No need again to explain the differences caused by the different locations the tests were performed concerning temperature, humidity, altitude, etc.

I respect your wanting to keep your pressure in the area you suggested, but remember those rifles were also chambered for the 7.62 NATO and it's unknown how many shooters shot 308 Win from them them with no foreseen problems. We also won't get into whether the 7.62 rifle actions were made of different steel, but the experts suggest that they weren't.

Your chronograph is a good help. If your load is way out of line with published data then you know something is amiss and you had better find out what that is. Some knowledgeable people in this field tell us to measure the head expansion on the case. One person goes about his testing in this manner: He keep increasing the powder charge and measuring the head expansion. When he gets to a figure that he wants to be at he stops there. Another person does nearly the same, but differs in that he keeps upping the charge until the bolt handle lift becomes stiff and then backs of 1.5 grains. I don't like the later nor approve of it.

I would continue on the path you have chosen as it sounds like a good safe one. I was always under the impression that if you had to push your caliber and load to dangerous level then you need a bigger caliber.

[376Steyr]

I use the Ken Waters ("Pet Loads" in Handloader magazine author) method of using a micrometer to measure the expansion ring on the cartridge case. The first chapter in his "Pet Loads" book goes into this in depth, but as I recall, if you get 0.001" expansion on a resized case, you are over the maximum and need to back off.

[vzerone]

I use the Ken Waters ("Pet Loads" in Handloader magazine author) method of using a micrometer to measure the expansion ring on the cartridge case. The first chapter in his "Pet Loads" book goes into this in depth, but as I recall, if you get 0.001" expansion on a resized case, you are over the maximum and need to back off.

I believe Ken measured the "head" of the case. The expansion ring is very near the bottom of the internal cavity of the case and just the fact of shooting from different size chambers would give an incorrect reading. The head part of the case is the part that is solid and it really shouldn't be expanding very much. The reason it doesn't expand as much is why you see the pressure ring because that ring is in the area that does expand.

Actually Ken done both. The one is called CHE (case head expansion) and the is PRE (pressure ring expansion).

[geargnasher]

Measuring the case head expansion per Waters is only valid if you do EXACTLY what he did and compare to FACTORY ammunition or ammunition loaded to known, tested pressure levels. Gotta have a benchmark to go by, something not easy to get for a wildcat. Common sense, a deep study of similar cartridge start/max pressure data with similar bullet weights and a broad range of powder burn rates will let you extrapolate a better load than, say, just using ten grains of Unique. A chronograph helps a bunch here to see where x grains of x powder with x bullet in YOUR rifle compares to lab data for similar cartridges. Take barrel length of test barrel and guestimate of bullet jump in test data ammo into account as well.

Or, just use Quickload with as much detailed data as you can find fields to input it and work up loads to a max of 10% under predictions for 44K psi to be on the safe side.

Gear

[vzerone]

Yes as geargnasher noted too many variables. You have to figure that up from a low set point with your rifle and your brass. You have to use the same brand brass and it has to be unfired. It's an iffy proposition if you're wanting to work on the ragged edge. Your best friends then would be a chronograph and a strain gauge.

[10x]

One of the reasons I purchased an Chronograph.
I assume that when I reach a velocity - that velocity is a result of the pressure published in the manual - despite being several grains of powder under the weight for that velocity and pressure.
I stop at the maximum velocity published as I assume that is the maximum pressure -I also stop if I do not reach max velocity but reach max grains of powder as published.
I have been known to abandon a powder because there are signs of pressure long before the published Max is reached.

[country gent]

I use several diffrent manuals and check each one for the given cartridge powder bullet combination if there is a big variation I may average them to get a general idea of maximum load and slowly work up to that in small increments watching primers conditions, head stamps , I will sometimes measure case heads against factory loads but this is also dependant on brass and other factors. A chronograph can give a rough idea but not a true peak or pressure reading, faster powders may generate the same velocities with higher peak pressures than a slow powder does. Ohler made a transducer set up that contacts glued onto barrel and gave a pressure reading. Published data is that as many things can affect this reading. Most are done in "labs" under controlled conditions as to temp barometric pressures, humidity, and such. Also older manuals may show heavier loads as newer manuals may have lowered pressures for some cartridges due to older firearms and or changes in components.

[JohnH]

Don't take this as "permission" to run wild but do remember that with equal bullet weights, a larger diameter barrel will drive a bullet to a greater velocity than the smaller diameter barrel with less pressure, or drive the same bullet weight to a higher velocity at an equal pressure. i.e.; a 35 caliber will drive a 200 grain bullet to a velocity equal to that of a 30 caliber at less pressure, or drive the same 200 grain bullet to a higher velocity than the 30 when both operate at the same pressure (given equal case volumes) Look at 30-06 and 35 Whelen data for a better understanding. I think the problem you will have in extrapolating data is that the 303 case is not equal in volume to the 358 Winchester. The 358 was also designed to operate at higher pressures than the 303. Others have mentioned that the Mk4 has been rebarreled to 7.62 Nato and they are correct in this, Both the British and the Indians did so in the 1950's. But the Nato cartridge operates around 48,000 psi, not the 55,000 of the 308 Winchester. This was a result of the M-14 and it's parent Garand and operating rod damage resulting from high operating pressures.. The 303 and the 7.62 Nato are actually similar in operating pressure and is the reason such conversions could be done safely. I have some Hornady 308 Winchester cases which were fired in an Ishapore conversion and I can't resize them, they stick in the dies regardless of the lubes I have tried. I would devoutly avoid running pressures greater than 45-48,000 psi in any Enfield.

[runfiverun]

I just went through this where I found data for the bullet and powder I wanted to use but the loads showed 2-3grain variances at the same velocity's and maximums.
so I started looking deeper. [meaning I pulled out more load books]
the one glaring difference turned out to be the cases and primers used.
just witching from a win primer in a Horndy case to a rem primer in a rem case meant an overload with a load 2 grs below maximum load in the other instance.

[Blackwater]

The .35/.303 Imp. version I have is just about equal to the .358, depending on what brass you're using, but as you say, I won't be driving it as hard pressure wise as I would a more modern .308. I'm sure th eold warhorse has proven itself grandly more than once, and feel like at this stage of its life, it ought to be coddled a little. I'm sure it's earned it. I'm thinking maybe 2450 with a 180, 2350 with 200 gr. Rem. PCL's (softest 200 I've found so far in my limited tests) 2250 with Speer 220 FSP's, and maybe 2100 with 250's if I ever feel the need to use the RN Horn. 250's I have. That's a lot bigger/tougher bullet than I'll need on anything in my area, normally, so it'll likely get scarce use, but I'd like to have a few, "just because." Tim's version pretty well maxes out the case capacity of the .303 parent case, and that gets possible velocities up where a longer shot would be easily possible. I doubt I'll ever need it at over 200, and anything in the 2000+ fps range should allow that kind of shot pretty easily. I've always just had "a thing" for the old Brit rifles, and will be restocking this one as soon as I can make up my mind about whether to scope it or not. I keep vascillating on that question. Making the decisions is always the hardest part on these projects, but it's also the part that I like wretching over the most, in actuality. No need to hurry it up, but I DO want to get it shooting well ASAP, with the std. irons. Wish my eyes were better! I guess you can't have everything, though?

[Blackwater]

I know that whatever machine one operates, whether it's a lathe or mill or typewriter or whatever, it's solely dependent on the operator. I also know (or at least think I do?) that the copper crusher method is a lot simpler than the piezo method. I know little of electronics, but I do believe the solid state stuff we use so commonly today tends to be sensitive to all sorts of things. I'm thinking this sensitivity, plus variations in the operators, is what is giving us sometimes widely divergent load data. Does anyone here know enough about the two methods, and have any insight on whether my sense, due to the above, is right or not? Piezos give a much more complete picture of what's happening when we fire a test round, but what creates some of these anomalies in widely divergent data is still a puzzle, and with an older rifle like mine, it'd be awfully good to understand the two processes better. Can anyone give any insights here on whether the great advantages of the piezo system come with disadvantages to the things I've mentioned here, or other factors I'm not familiar with?

I know they say curiosity killed the cat, but NOT knowing stuff has probably hurt a lot more people, and messing with things that CAN blow up if we make an error in judgment (not likely, but never impossible) keeps me trying to learn all I can. Thanks to anyone who can comment knowledgeably on what is just a sense I have, and have questions about.

[Tatume]

While not being an expert on the subject, I've read reputable sources who say the pressure reading often depends very much on the operator. Professional pressure guns often do not have a lock, per se. Instead, they have an external spring-powered striker. The operator pulls back on the striker and releases it to fire the cartridge. If the operator pulls smartly and releases with a snap, the striker hits hard. If he pulls back and holds the striker, and then gently releases the striker, it hits with much less vigor. The former will give a higher pressure, because the primer is struck more positively, and ignites fully, right away. The latter will give a lower pressure, because the primer is not so energetically ignited. Operators have demonstrated this phenomenon quite conclusively.

The energetic strike and higher resultant pressure also produces more consistent pressures, which one might suppose could contribute to greater accuracy. This is why I'm gradually getting rid of all my reduced power hammer springs in my revolvers, and moving back to full strength or extra strength springs.

[Bjornb]

Blackwater, your cartridge is virtually identical to the 35 XCB (30x57)both in length and volume. I have been testing that cartridge extensively over the last 6 months or so, and I'll soon take delivery of the third rifle from Goodsteel (this one with a 1:18 twist barrel bored by JES, just to see what a super slow twist will produce. The other 2 rifles are 1:14).

If you're interested, PM me and I'll share a number of bullet/powder combinations, both those that worked and those that didn't. The short version: IMR 3031 is your friend, both with cast and jacketed.

[shooter93]

Do what Gear said....use quick load or have someone who has it run the loads for you with all the information you can put in.....bullet and powder weight, oal makes a big difference. I have quick load but have never taken the time to learn it well but a member here has always run the numbers for me. It does work very well and you can use the start low and work up method on paper and then start again with the gun. It's by far the easiest way for me when working with "odd" rounds or guns.

[Hick]

I do lots of comparing between manuals and using my own chrony data. I plot a graph for each powder/bullet combo, graphing grains of powder versus velocity using all the data from the different sources. The data points never make a nice straight line, but they usually have a smooth general trend of increasing velocity with increasing load. Putting all the different sources on one piece of paper makes it easier to see when one source looks out of whack compared to all the rest.

Admittedly, velocity and pressure are not the same thing-- but they are connected. So I watch out for a source that gives a reasonable velocity for an unreasonably high load, and if I see that I suspect an error.

[W.R.Buchanan]

I always compare several manuals for load data when I start out with a new cartridge. Those manuals really need to be both old and new, so that you get a good cross section of what was considered safe once, and what is considered safe now. Keep in mind new stuff usually was compiled using Newer Equipment, and could be either more accurate or more conservative, owing to the consideration of the age of the guns you will be shooting this cartridge.

I have a #4 Mk1* Long Branch rebored by JES to 35-303. His recommendation was to start with 35 Remington loads.

Further research revealed a .35 Krag round that data is available thru "Load-Data .com" out of Handloader Mag. The Krag round and the .303 round are very similar so the two can be compared head to head favorably.

The last similar cartridge is the 35 Winchester, and Load Data for it in Win 1895's, was compared to .35 Krag loadings which were again very similar.

Interpolation of load data is not new and anyone who is venturing into "Unknown Territory" will have to do it to some extent.

Obviously starting low and working up is what must occur. Using a Chronograph to find velocity which is directly proportional to pressure and comparing that to known pressures for the same caliber and similar bullets will get you where you need to go. There is plenty of source material on pressures generated by .35 Rem, .358 Win and .35 Whelen so that you could find a velocity that equates to the pressures you want to stay below.

I plan on using this same technique when I work up a load for the two Bullets I want to use in my gun. A 250 gr Hornady Roundnose and a 250-280 gr Cast. The cast boolit is no problem, I'll start at 25 gr of 5744 and increase that until I see 1600-1800fps,,, Lots of room here to stay out of trouble.

For the J bullet I will compare .35 Rem, .358 Win and .35 Whelen loads for 250 gr bullets. The heavy bullet loads for .358 and .35 Whelen are all going much faster than I care to shoot so starting out at @1600 fps and working up until I can't stand it anymore will be the method I use. I will give out long before the gun would.

But knowing the velocity for a given bullet I will be able to approximate the pressures being generated close enough to stay well below anything dangerous to a #4 action. If I can stand 2000 fps, a 250 gr Roundnose will perform as advertised. I only have to shoot enough of them to define the trajectory to 200yards as I'm not going to take a shot on game beyond that with an Iron Sighted Gun. Once it's written down I know exactly what it will do and then not exceed that limit.

Also the J bullet loads will probably not get used a whole lot and more will get shot off the bench for load development than ever get shot in the field. 100 bullets in a box will outlive me easily.

The gun will primarily be shot with Cast Boolits at Short Range Silhouette shoots. 50-200M

I have an 2 part axiom for loading cartridges. #1 You don't need to load beyond 90% of maximum to achieve desirable results on Game.

Example: A 250 gr .44 SWC will go completely thru an Elk at 900 fps. This is achievable from a .44 Special Revolver. My .44 Rifle pushes that same slug at 1600 fps. That pretty much guarantees I'll never find the boolit. Also everything in N/A has been killed thousands of times with a .30-30 so anything over that is going to be enough gun. Using these two examples I will probably never own a .300 Win Mag.

#2 You damn sure don't need a hotrod load for shooting Steel or Paper Targets. If I can't tolerate 40 rounds in 1-2 hours then its too much.

For shooting game you only have to shoot once or maybe twice at a given animal so I can take a little more push back in that case.

My whole point of this post is to convey the idea that with the cartridge you are loading for you have tons of leeway to start and be safe. 44K psi is well within my 90% rule.

Hope some of this helps.

Randy

[MBTcustom]

The rifle I built was designed to bring a margin of safety to load development. I knew that the British action was very springy, and was designed to accept a certain amount of bolt thrust which the 35 caliber would undoubtedly modify more or less. I was after a precision, low pressure paper patch rifle, so I straightened the walls of the cartridge in order to reduce bolt thrust to a minimum. I also used a thick barrel of modern steel, so higher pressures are easily contained both radially and linearly. Add to that the fact that the bolt nose of the British seals the barrel so tightly when closed (I believe Col. Hatcher mentioned this specifically in his legendary Notebook) and you have a rifle with a pretty large margin of error.
In fact, I had planned on ramping up the pressure later on, but that would require my building a FL sizing die in order to keep the brass from sticking in the chamber which would take the project in a different direction than originally intended.
So, my advice is, use 358 Winchester loads, and watch your chronograpgh. Find a nice gentle load that pushes a 250 grain bullet out of there nice and easy at less than 1500FPS, and enjoy a rifle that will never wear out your brass, that you can load in the field with the tools provided, and knock down anything less than bear.
That was the original intent.
You might also try some black powder loads (something else I never got around to) as that will put you precisely in the range I am talking about.

[Blackwater]

All comments well taken, and particularly yours, Goodsteel. Your points are particularly well taken, and I understand them all. I just don't need a whole lot of oomph, but for certain special uses, I think J-bullets would at least be interesting, so need to work up some loads with good velocity to get the expansion I want on our smallish Southern whitetails. Too late to let my grandsons use it this year, and get some appreciation for what it really takes and doesn't to take our whitetails here where a 200 pounder is a big one. If I don't teach them some of these things, nobody will, and few can, so ... I just want them to get as much understanding as I can impart to them, and let experience do the rest. That's the only way any of us learns, after all, and this old gun is a really good tool to teach them some of that.

Most folks here suffer from the "bigger is better" syndrome, and if they have a deer run off due to a miss or poor shot placement, they go to a 7mm or .300 mag., which experience tends to show just don't work as well as std. calibers on most of our deer here. The super fast ones, which I regard as anything much over 3000 fps., have to use more "controlled expansion" bullets to keep from nearly cutting them in half, and then, they often don't expand quickly enough on slightly built deer, so they actually often work LESS well than the std. calibers like .270, .308 and '06, et al.

And with shooting constantly seeming to get more and more expensive, cast will let them shoot a LOT more, and shooting a lot is the ONLY way to get really good. They're darn good shots now, even the 12 year old, and better than most men I know already, but they still have room for improvement. Learning to squeeze off without moving the barrel is the next step for them both, and that'll be really interesting to watch. They're so active in sports and church that there's precious little time, and low recoil loads will let them get more experience quicker, too, which is also a good thing.

And if I can ever make up my mind to scope or not scope it, that'll be my biggest hurdle. I need a scope, but want an iron sighted "big rifle" for them to use, just to learn to do it and appreciate the benefits of a good scope. Need to get that done before stocking it, so .... I keep vascillating and arguing with myself, but it shouldn't be long before I settle the mater by just getting tired of waiting, and do something, one way or the other.

Again, thanks for the insights, and I didn't expect anything earth shaking, but with the quality of folks here, you never really know, so just had to ask. It's only where I can't use primers as a pressure indicator that I get rather uncertain as how to proceed, and with a rifle like this, I just want to treat it right for the long haul. I no longer regard my rifles as "disposable," and like treating them more gently than I have in the past at times. And my curiosity has taken on new directions as well, so .... this is a really great rifle to pursue what I want to do now, and it's gonna' be interesting playing with it. Thanks to all.

[35remington]

Waters did indeed measure the expansion ring not the case head.

When rear locking actions are under duress cases grow noticeably after being shot. Try to avoid the clear indications of action stress and the action won't be stressed. Compare to quantify at different load levels and chronographed velocities.

Sometime we need to have a discussion about straight versus tapered cases and bolt thrust.