Effects of varying powder charges?

[billmc2]

I have no formal training with any kind of ballistics. I'm learning as I go. I know that too much powder is bad but so is too little powder. Too much powder can lead to over pressure conditions and possible kabooms. What happens with too little powder?

At the moment I'm playing with 45 ACP, Accurate No 5, and a new MP mold 45-225. With Lyman #2 my bullets are coming out at around 224 grains for the solid bullet (haven't played with any hollow points). I'm powder coating the bullets. In order for me to get the assembled cartridge to fit both my gun (HK 45) and my Cartridge gauge I have an OAL of 1.180".

Yesterday I loaded and shot several different loads ranging from 6.9 gr to 7.9 gr in 0.1 grain increments. Average velocities ranged from 796 to 891 fps. Charges below 7.3 grains have widely spaced velocity spreads and large Standard Deviations. Once I get to 7.3 gr charge, these numbers tighten right up and look (to me anyway) what I'd consider to be normal ranges.

Am I correct to assume that the lessor charges are what is giving me the velocity spreads and Standard Deviations that I'm seeing? Are those large spreads and deviations signs of too little powder (which I assume means not enough pressure). What are other signs to look for when it comes to lesser charges? (I'm not considering a stuck bullet in this grouping of symptoms.)

[TD1886]

It sounds to me like that's not a good powder for your what you are loading. Have you tried another powder? The main culprit of high SD's is varying velocities, yes, there are other things, but that is the main one.

There are too many things to name of using too little of a powder. Maybe Larry Gibson will chime in here and explain that to you.

[bruce381]

you are fine there is a sweat spot for most pistol charges and too low will have more larger SD and sometime smokey residue or cases . as you go up it cleans up and you hit a good load normally. stay within powder mfg recommendations and u will be fine.

[chriskendziora]

The powder hits a sweet spot and too low can cause issues. Not sure what powder you're using too help further. Some powders have a dual pressure curve found put the hard way once with BLC2. I think too low is called detonation.

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[45_Colt]

Am I correct to assume that the lessor charges are what is giving me the velocity spreads and Standard Deviations that I'm seeing?

Yes.


Are those large spreads and deviations signs of too little powder (which I assume means not enough pressure).

In this case, yes, not enough powder. The charge isn't burning consistently as the pressure doesn't get high enough for the powder you are using (AA #5).

The 2003 AA loading guide shows a minimum of 7.7gr for a L 230gr RN. For 891 fps, using #5.

For lower velocities AA #2 is a better bet:

The 2003 AA loading guide shows a minimum of 5.0gr for a L 230gr RN. For 800 fps, using #2.

The Accurate Arms loading manuals are free on line. Best to get a recent one and check out the various powders along with the boolit weights. Then pick the powder that covers the velocities that you are desiring.

45_Colt

[gwpercle]

Too Little Powder and the boolit will not exit the barrel ... it will Stick in the bore .
Be extremely careful of this ... another shot fired behind a stuck boolit will damage something ... usually the rifle barrel but sometimes more damage occurs .
Be Very careful with Minimum Charges or the case that gets No Charge , Look and Listen for a shot that doesn't sound "right" ... Stop and check the bore for a stuck boolit !
It's Okay to get Anal and OCD about getting one charge , of the correct weight , in each case ... My loading method lets me eyeball the powder in a case 3 different times before boolit seating ... You can't be too careful when loading ... you must have the right powder and the right charge ... not two charges and not 0 charges in that case .

45_Colt's advice , see post above , is right on about powder . If the Accurate Arms loading Guide is still available , send off for one ... Most Excellent Data contained in the Guide .
Load Safe ,
Gary

[Winger Ed.]

Am I correct to assume that the lessor charges are what is giving me the velocity spreads and Standard Deviations that I'm seeing? )

As said, often loads will have a sweet spot in relation to the weight of the powder charge.

Other times, for lack of a better explanation,
you'll find that certain powders, boolits, and combinations of the two that one or more guns simply don't like.

It reminds me of a life long friend. I used to ask people questions just to see how they'd answer.
I asked various people:
If a dog likes to hang their head out the car window at 50mph, why do the get mad when you blow in their face?
Rather than admit they didn't know-
Some would go off into describing about the pressure differences on their ears & nose, or some other bs.
My buddy answered by saying- "They just don't like you blowing in their face".

I've never had the time or inclination to go off into uncharted waters with my reloading, much less start at the max. and work up.
I've found I normally get my best performance/accuracy by using the published data in the books at about 80% or their max. listings.

[charlie b]

This is a well documented conclusion about light charges with some powders. The worst culprits for me have been double base powders. Win noted that W296 should not be downloaded. Some people assumed that to mean the gun might blow up but later notes from Win explained that below a certain pressure the powder would give erratic results, not dangerous, just erratic.

That is why it is best to follow the book loads. I especially like to reference the loads recommended by the powder mfgs for this reason.

There are some powders that will do ok outside their 'normal' pressures. When you deviate from the norm you are on your own.

[Pirate69]

Based on the data given, I ran the 7.9 grain Accurate No. 5 load through both QuickLoad and Gordon. Both indicate this load is above the maximum allowed pressure. I think the 1.18" OAL is an issue with this charge. Data that I am seeing says it should be around 1.23". An OAL of 1.23" gives about 85% of the allowable max per GRT.

Just a word of caution.

[billmc2]

Hey guys, thanks for the info.

First, it was pointed out to me that I made a typo with the mold designation. I had originally posted it was 45-255, that is wrong. it is 45-225. So I edited the above post to correct that.

A couple of you mentioned that the "powder" will have a "sweet spot". I didn't know that but looking at my data I can see where that happens.

People have asked about the load data I used. I couldn't find data for a 225 gr bullet, so I used data for a 230 gr bullet. I was looking at the 2nd Edition of Lee's Modern Reloading, 4th Edition of Lyman's Cast Bullet Handbook and the 3rd Edition (which I believe is the most recent) of Western Powders Handloading Guide.

My bullet is shorter than a 230 gr Keith bullet mold I have, which is 0.622" long; uncoated it has a length of 0.582". The loading manuals call for an OAL of the 230 gr bullet to be 1.230"; as I stated mine is 1.180"; its sized this short to fit in my chamber. Knowing that my OAL is shorter than specified, I knew I'd need less powder but I didn't know how much less. I picked up a copy of Quick Load (which for me has a big learning curve; and I'm still behind the curve). I used the function in Quick Load to generate charges above and below a particular starting load, I chose 7.4 gr to start with and let Quick Load go up and down from there.

I knew that some of my loads would be to small but I didn't know what the symptoms would look like. What I'm trying to do, is understand what is happening. Rather than just following a recipe and leaving it at that; I'm trying to learn what is going on so that, at another time, I can diagnose problems when they come up. Now I'm not saying that I'm discarding the recipe, but as in this case, when there is not an exact recipe for the bullet I'm using, modifying the published recipe so I have something that works safely with the bullet I have.

Pirate69 - your response came in while I was typing this particular post. I also ran this through Quick Load and saw that 7.9 gr was above the pressure for 45 ACP but it is just below the pressure limit of 45 ACP +P. My pistol is rated for +P loads so I'm thinking it would be safe to document what is happening. As it turns out, with this particular gun, I'm finding in general, whatever loads I try, including factory loads, they all come up a little short of what is published.

Edited to add: I did fail to mention that I have checked my brass and when necessary trimmed them, so that all my brass is the specified trim to length of 0.898".

[billmc2]

The powder hits a sweet spot and too low can cause issues. Not sure what powder you're using too help further. Some powders have a dual pressure curve found put the hard way once with BLC2. I think too low is called detonation.

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I really don't have a good grasp on the idea of pressure curves and what they mean, yet; still working on that.

Could you please describe what you mean by a dual pressure curve? Looking at my data and your comment, I noticed that after a "sweet spot" (that was pointed out to me) my numbers diverge and then later come back together again. Could this be the dual curve you speak of?

[billmc2]

Yes.



In this case, yes, not enough powder. The charge isn't burning consistently as the pressure doesn't get high enough for the powder you are using (AA #5).

The 2003 AA loading guide shows a minimum of 7.7gr for a L 255gr RN. For 891 fps, using #5.

For lower velocities AA #2 is a better bet:

The 2003 AA loading guide shows a minimum of 5.0gr for a L 255gr RN. For 800 fps, using #2.

The Accurate Arms loading manuals are free on line. Best to get a recent one and check out the various powders along with the boolit weights. Then pick the powder that covers the velocities that you are desiring.

45_Colt

Thank you. You answered my questions. I did make a typo error earlier and my bullet is supposed to be 225 gr, not 255 gr.
Western Powders are now publishing the Accurate Data. I bought a copy of their book earlier this year, its the 3rd edition.

[billmc2]

The powder hits a sweet spot and too low can cause issues. Not sure what powder you're using too help further. Some powders have a dual pressure curve found put the hard way once with BLC2. I think too low is called detonation.

Sent from my SM-G970U using Tapatalk
After reading your post again and noticing the word detonation, it made me think of gasoline in a cylinder of a motor. Pinging. That is also called detonation; it is not a good thing. I kinda view that as a hammer whacking into the piston. Instead when the gasoline burns correctly, there is a constant push against the piston from the flame front. As the piston moves, the air/fuel mixture follows the face of the piston, pushing against it.

Now that you point that out, it sounds as if we want to see the same thing with the bullet (bullet = piston, case = cylinder).

[unique]

Probably powder variation in case is culprit.
Less powder in a case means more space. More space means powder position varies more. Take your minimum loads and raise muzzle up before firing and then slow lower before firing and measure velocity...now do that again with muzzle down before firing. what you are doing is placing powder charge on primer in first case and in second case powder is further away from primer. Makes a big difference in pressure/velocity. It is one of the tests I do when selecting powder/charge combination.

[Dusty Bannister]

Probably powder variation in case is culprit.
Less powder in a case means more space. More space means powder position varies more. Take your minimum loads and raise muzzle up before firing and then slow lower before firing and measure velocity...now do that again with muzzle down before firing. what you are doing is placing powder charge on primer in first case and in second case powder is further away from primer. Makes a big difference in pressure/velocity. It is one of the tests I do when selecting powder/charge combination.

This would likely influence a large rifle cartridge. Given the length of the interior of the 45 acp case with a bullet seated, and loading between 7 and 8 grains of a relatively slow burning pistol powder, I would question if this is such a significant factor. Has this been your actual experience with the 45 ACP?

[unique]

Yes with 45acp and bullseye. OP said No5 was being used and that is a ball powder and ball powders tend take a bit more energy to ignite so I would think powder position would be factor for sure. Only way to know is to test for it.

Believe it or not, one cartridge that I found that was NOT sensitive to powder position was 45-70 with 16 grain unique powder. If i ran 45-70 with rel7 then got to point of click-boom based upon powder position...but I digress. Of course if your powder charge is >90% of volume then variations are small or non-existent.

[Wayne Smith]

One issue is your choice of powder. Ball powders are very convenient and measure very easily, but they also have a 'sweet spot' in the amount of pressure needed for them to burn completely. Other types of powder forms have much larger range of pressure that allows them to burn completely. With a ball powder if your charge does not reach the minimum pressure needed the powder will not burn completely and thus become erratic. Bullseye and Unique do not have this characteristic, so that is the reason why unique's 45-70 unique load had no problem and his RE7 (a ball powder?) might have.

[dverna]

As said, often loads will have a sweet spot in relation to the weight of the powder charge.

I've never had the time or inclination to go off into uncharted waters with my reloading,

I am in the same boat. Putting .45 ACP loads over a chronograph seems like a waste of effort to me. In fact, I feel that way about most pistol loads. If the load groups well, chasing SD and ES seems pointless. But then I rarely shoot pistols past 50 yards anymore.

Makes sense to use loads for 230 gr for your 225 gr bullet. This is not rocket science.

[Winger Ed.]

Makes sense to use loads for 230 gr for your 225 gr bullet. This is not rocket science.

That's where I'm at. And I try not to over think this stuff.
There is a fair amount of wiggle room in the published data and still be safe.

My .45 cal. 405 mold for the .45-70 actually casts out with my alloy at 424 or 425.
I use the 405 gr data and haven't lost any sleep over it, blown up the Marlin, or shot my eye out.:bigsmyl2:

[45_Colt]

Thank you. You answered my questions. I did make a typo error earlier and my bullet is supposed to be 225 gr, not 255 gr.

I did the same typo, just changed it to 230 gr (from 255). Here is the section from the 2003 AA load manual:

316255

45_Colt

[billmc2]

I still consider myself to be relatively new to hand loading. I got started only a couple of years ago, right around the same time that we were hit by the plague. So I don't have the amount of experience that many of you do. I also don't have enough time to accumulate that experience. Although I'm not as old as some of you, I'm not that young either. In about 7 months I'll be forced to participate in medicare. I also don't have anyone teaching me how to do this. I have books and you folks here on this forum.

Because I don't have anyone teaching me, the only way I know of, to confirm that I did something correctly is to measure it. If I've followed all the bread crumbs along this path correctly, I've concluded that pressure is significant. Unfortunately for me, I can't measure pressure. I can, however, measure velocity. I've been lead to believe that there is a relationship between pressure and velocity. I think it goes something like this; if the velocity is in the range of the published data, then the pressure is also in range. If the velocity is above the published data, odds are that my pressure is above where it supposed to be. If my velocity is below the published data, then my pressure is most likely below as well. Until I have decades of experience (ain't happening, not enough time left) I'll use my chronometer to measure every thing I load.

Powder Selection. This I found very easy to determine. If you think back, just a little while, you'll recall that reloading components are in short supply. I based my decision upon what was sitting on the shelf (shelf being a metaphorical term, initially I order off the internet, more recently its been the physical shelf in the LGS). According to the pile of loading manuals (not counting the electronic copies, I just counted them; I have 10), I can use Accurate No 5 in more than one cartridge. So far, I’ve stuffed it into 32 S&W Long, 32 H&R Magnum, 380 ACP, 45 ACP, 45 Colt, and 44 Special, I haven’t tried it in 9mm yet but from memory I think I can use it there as well.

I have been able to pick up some other powders since I started, that I will get around to playing with, but for this particular exercise I'm using Accurate No 5.

[45_Colt]

Understand where you are coming from. Not sure why it was posted to not chronograph handgun loads. Nothing wrong with doing that. I do it all of the time. If anything just to make sure the load is in the ball park.

As far as 'this powder' and 'this load', be aware that the published minimums should be held too. There are loads/powders below the minimums that can cause havoc. Not just stuck projectiles, but worse.

You can stay with #5, just load above the minimum recommended. And watch the cartridge OAL. Which will vary between a RN and a FRN boolit. What matters is how much of the boolit is in the case.

Case volume on a fully loaded cartridge matters. Less volume, more pressure.

45_Colt

[Dusty Bannister]

I would think that just using the chronograph to establish a consistent burn without using an actual target to verify accuracy in grouping is not of much benefit. It will show velocity consistency but absolutely nothing as to bullet stability, or exceeding the alloy strength.

What happens in the case is important, but more important is what happens after the bullet leaves the barrel.

[billmc2]

Understand where you are coming from. Not sure why it was posted to not chronograph handgun loads. Nothing wrong with doing that. I do it all of the time. If anything just to make sure the load is in the ball park.

As far as 'this powder' and 'this load', be aware that the published minimums should be held too. There are loads/powders below the minimums that can cause havoc. Not just stuck projectiles, but worse.

You can stay with #5, just load above the minimum recommended. And watch the cartridge OAL. Which will vary between a RN and a FRN boolit. What matters is how much of the boolit is in the case.

Case volume on a fully loaded cartridge matters. Less volume, more pressure.

45_Colt

In trying to understand all this stuff, on my own I came to the conclusion you just stated about case volume.

People keep talking about the load data and OAL. I know that as I seat the bullet deeper into the case, case volume will decrease but pressure will increase. Normally the published load data will give you the numbers you need. In this particular instance I don't have that information. The bullet I'm using is not addressed in the manuals I have. Again it is the MP 45-225. I think you'd call it a Wide Flat Nose. When I look in the load manuals for a 230 gr lead bullet, most specify an OAL of 1.230". With this bullet and my gun I can not use that length, it don't fit. Starting loads of Acc #5 for a 230 gr bullet with an OAL of 1.230" is 7.7 grains.

Using both a cartridge gauge and my barrel, I kept seating the bullet deeper and deeper until it finally fit. I ended up at an OAL of 1.180". My bullet is not as long as a RN bullet so I would expect to see less intrusion into the case but at my length, I believe its significantly deeper than what is normally called for. As was pointed out earlier 7.9 gr of powder is over pressure (estimated by Quick Load). Correct me if I'm wrong but with less case volume, to reach an equivalent pressure (velocity) I need to use less powder. How much? I don't know.

Looking at a printout from Quick Load, I see that 6.9 gr Acc 5 has an estimated pressure of 16386 psi. Is this enough? I don't know. Load and shoot it and see what happens. When I did that the gun cycled just fine. The velocity spread and standard deviation was large. Thus I asked my question. You guys tell me that what I observed is an indication of not enough powder (not enough pressure), so the powder charge needs to go up. As I said previously, I loaded a range of powder amounts and recorded the velocities. From my results, for my gun, with this powder, and this bullet, my starting charge should be 7.3 gr of powder. What's the top end? I don't know. I did shoot 7.9 gr of powder but the chrony did not record all of the shots; I need to shoot it again. What I did get is an average velocity of 914 fps and Quick Load estimated my velocity should have been 955 fps with pressures in the +P range. For the velocity I did see, Quick Load's estimate of pressure occurs around 7.6 gr which is 0.3 grs less than what I needed to reach the same point, and falls just below max pressure of the 45 ACP.

Looking at my results I'll say that my gun is not generating the same pressures as what normally be expected. I'll make a guess here and say that my pressure is lower than predicted for the specified charge because my velocity is lower than predicted for the specified charge.

I would not have this information without using the chronograph. I don't think I can start tweaking a load and looking for accuracy until I know the range of powder charges I can use. I don't want to be sticking bullets, nor do I want to blow up my gun (hand, fingers, etc., I won't mention eyes because its not a BB gun).

From what y'all telling me, if I keep seeing erratic velocity spreads and SDs, I'll probably need to try a different powder. What I'm gleaning from this conversation is the next powder should be a little faster than the No 5.

If my logic and reasoning is way off base, please let me know. I'm not going to be able to shoot again for several days do to weather conditions, so I won't be able to give any feedback on my results for a bit.

[Dusty Bannister]

Are you obsessing on chamber volume? Are you obsessing on ballistic numbers. Are you even considering where the bullet hits the paper? Ballistics are sort of meaningless if you can not hit the target reliably. Measure the groups on the target, then verify the numbers from the chrono. You know that your charges are not going to be dangerous with excessive pressures.

[billmc2]

Are you obsessing on chamber volume? Are you obsessing on ballistic numbers. Are you even considering where the bullet hits the paper? Ballistics are sort of meaningless if you can not hit the target reliably. Measure the groups on the target, then verify the numbers from the chrono. You know that your charges are not going to be dangerous with excessive pressures.

I'm seeing this after the PM.
Nope, I'm not even beginning to consider where the bullet hits the paper. That will come later. I don't think I'm obsessing on chamber volume. I think I'm trying to work within safe pressure. How am I supposed to know if my charges are safe if I don't measure them? Once I have charges which I know are within the pressure standards specified, I can start working on all the other stuff. I'm thinking, that because the charges are so far removed from what is published in a manual, I'm essentially working without any published data.

Yeah/Nay?

[JonB_in_Glencoe]

If you are just trying to work up a load, then I think you are digging too deep into the minutiae.
OR
If you are trying to learn how to precisely define a load data range [that doesn't yet exist] per chamber pressure, then you need instrumentation to measure pressure.
Quikload is a wonderful tool, but don't trust it 100%


SNIP>>>

Once I have charges which I know are within the pressure standards specified, I can start working on all the other stuff. I'm thinking, that because the charges are so far removed from what is published in a manual, I'm essentially working without any published data.
I don't agree that they "are so far removed from what is published"
I think you've already got the charges [roughly] from what you've done so far and they are right inside what is published.
7.3 to 7.9


SNIP>>>

Nope, I'm not even beginning to consider where the bullet hits the paper. That will come later.
I say NOW IS THE TIME to break out the targets and see where the holes are.
While you've shot the 7.9 already without blowing up your H&K, you should be safe to venture that far again. BUT, always work up...and when you are at the 7.6 range, you should be watching for overpressure signs, flat primers, recoil/report, and depending on gun design I use the distance the pistol launches the fired cases...and using a Chrono is great also, but it shouldn't be the only measure.

One last thought,
If you don't get the desired accuracy with AA#5 and decide to try another powder. Please realize that all powders have differing characteristics, besides burn rate, They all have their own unique pressure curve. Powder companies have designed powders for specific applications. Poor accuracy with a slower powder like AA#5 doesn't mean another slower powder will also be inaccurate. How ignitable a powder is, can be a major factor, sometimes adding a Mag primer to the mix will help. What I would suggest when choosing another powder, is to research on castboolits what other members have had success with.
Good Luck.

[Larry Gibson]

Smokeless powders used in cartridges do not "detonate", they burn. An S.E.E. occurrence is not caused by a "detonation" of the powder. A small cartridge such as a 9mm or 45 ACP can contain only so much powder. That given amount of powder has only so much potential energy. That energy cannot be increased beyond the potential of the amount of powder regardless of the method of ignition.

Every smokeless powder has a minimal pressure where it burns efficiently. That state is influenced by the ignition and the rise to pressure of the time/pressure curve commonly referred to as the "pressure trace". What the OP is observing with his reduced loads is, for the powder used, the powder is not reaching sufficient pressure or rise to pressure to burn efficiently. It's as simple as that.

As I've said many times on this forum over the years regarding powders for which no data is available; "many times we may have a powder we really want to use in a certain cartridge but "having" and "wanting to use" many times does not make that powder suitable to use." I suggest to the OP he simply move on to a more suitable powder conducive to reduced loads [Bullseye, 700X, Red Dot, Unique as examples] if that is what he wants.

[justindad]

billmc2 - I have been asking similar questions, and I’ve found some surprising answers and even more questions. My recommendation for you is to get the Lyman Cast Bullet Handbook #4 and pick a mold contained therein. The molds I would recommend don’t have load data for AA#5, so I guess Lyman #452374 is your best bet (I hate Lyman’s quality)… maybe post a WTB add in S&S and ask for a mold made before 1980.
*
After you have enough experience loading with a bullet that is in a manual, you can then use your MP bullet with more confidence (comparing results between bullets). You could find the max charge with unburnt kernels (same gun, same powder, same brass, same primer, same alloy, loaded on the same day) for both bullets, and those two charge-bullet combinations should be close in pressure.
*
Dusty says you’re safe on pressure, so I believe you are. Nonetheless, pay attention to how your gun behaves because it may tell you when your pressures are too high.

[billmc2]

Smokeless powders used in cartridges do not "detonate", they burn. An S.E.E. occurrence is not caused by a "detonation" of the powder. A small cartridge such as a 9mm or 45 ACP can contain only so much powder. That given amount of powder has only so much potential energy. That energy cannot be increased beyond the potential of the amount of powder regardless of the method of ignition.

Every smokeless powder has a minimal pressure where it burns efficiently. That state is influenced by the ignition and the rise to pressure of the time/pressure curve commonly referred to as the "pressure trace". What the OP is observing with his reduced loads is, for the powder used, the powder is not reaching sufficient pressure or rise to pressure to burn efficiently. It's as simple as that.


Larry, would you know of a book I could pick up that could teach me things like you mention here? This is the first time I've come across terms like time/pressure curve or pressure trace. I'm aware that a particular powder needs a particular pressure (but not any specifics to go along with that statement), but that's where my knowledge ends. I know some powders are fast and some powders are slow and those terms are relative to the powders you are talking about. Beyond that I really haven't got a clue as to what that all means nor how to apply it.

What does S.E.E. mean?

Because I've read here (somewhere) about needing a certain pressure to burn correctly, is why I asked if that might be my problem.

[billmc2]

billmc2 - I have been asking similar questions, and I’ve found some surprising answers and even more questions. My recommendation for you is to get the Lyman Cast Bullet Handbook #4 and pick a mold contained therein. The molds I would recommend don’t have load data for AA#5, so I guess Lyman #452374 is your best bet (I hate Lyman’s quality)… maybe post a WTB add in S&S and ask for a mold made before 1980.
*
After you have enough experience loading with a bullet that is in a manual, you can then use your MP bullet with more confidence (comparing results between bullets). You could find the max charge with unburnt kernels (same gun, same powder, same brass, same primer, same alloy, loaded on the same day) for both bullets, and those two charge-bullet combinations should be close in pressure.
*
Dusty says you’re safe on pressure, so I believe you are. Nonetheless, pay attention to how your gun behaves because it may tell you when your pressures are too high.

Ain't that always the way? Questions always lead to more questions.

Its funny you mention that bullet because Dusty also just told me about that bullet. I do have a copy of the 4th Edition Cast Bullet Handbook. I mentioned to Dusty that I'm not sure how I overlooked that particular listing. I do see, for that bullet, data for Acc 5 and the loads I was trying fall within the range they list. The difference is OAL. I don't have their bullet to measure so I don't know how similar they are. This is a link to the mold I bought. https://www.mp-molds.com/product/mp-452-225-hp-pb/

When I started to first have some problems with this gun/bullet combination, I thought of what you suggested, looking for a mold that has published data. I shied away from the Lyman molds because they are iron. I'm in FL. Last Thursday the dew point at my house was 77F. I don't want to deal with rust issues. When I can, I'll buy a brass mold and if brass isn't available I'll go for aluminum.

I've only looked quickly, but I think RCBS, SAECO, and Lyman are all some form of iron molds. I haven't seen data for the specific molds I have bought. The last one came from MP; I've also bought brass and aluminum from Arsenal molds. I picked up an aluminum mold for 6.5 Grendel and stashed that away for future use, at the moment I don't recall which vendor. I'm not ready for rifle yet and that was listed as the last one from a group buy order.

[Pirate69]

billmc2,
I may have missed this information in the previous posts. What is the measured length of the boolit that you are casting?

[JonB_in_Glencoe]

SNIP>>>

Its funny you mention that bullet because Dusty also just told me about that bullet. I do have a copy of the 4th Edition Cast Bullet Handbook. I mentioned to Dusty that I'm not sure how I overlooked that particular listing. I do see, for that bullet, data for Acc 5 and the loads I was trying fall within the range they list. The difference is OAL. I don't have their bullet to measure so I don't know how similar they are.

Maybe ask Bazoo
I wonder if he has his website online yet?

https://castboolits.gunloads.com/showthread.php?454189-Bullet-Comparison-APP-Samples-WANTED

[billmc2]

billmc2,
I may have missed this information in the previous posts. What is the measured length of the boolit that you are casting?

I've measured several bullets coming out of the mold. The length seems to vary slightly, but most are coming out at 0.582".

[45_Colt]

What does S.E.E. mean?

Because I've read here (somewhere) about needing a certain pressure to burn correctly, is why I asked if that might be my problem.

Since 'ole hit and run won't answer...

SEE stands for Secondary Explosion Effect. The term is used when a firearm blows up when using light charges of powder. This is why I mentioned to stay above the minimum charges from loading manuals.

The biggest issue with a SEE is that, so far, ballistics labs can't replicate it on demand. Sometimes it occurs, but most of the time it doesn't. Same conditions, same gun, same everything, but won't occur on enough of a regular basis.

As for it being your issue with the light loads of AA #5, no. That is just a case of not enough pressure to get a good burn. In this case it will usually leave unburned powder in the barrel.

{edit: forgot some links}:

https://reloadammo.com/light-loads-can-explode/

https://sportingshooter.com.au/ask-uncle-nick/secondary-explosion-effect-a-reality/

45_Colt

[justindad]

<snip>
I shied away from the Lyman molds because they are iron. I'm in FL. Last Thursday the dew point at my house was 77F. I don't want to deal with rust issues. When I can, I'll buy a brass mold and if brass isn't available I'll go for aluminum.

I’m in SC where the grass stays wet with dew until 7PM on a 90 degree day. I also shied away from iron molds, but since realized they take far less maintenance and can be ran much harder than aluminum or brass. They also drop boolits far easier. Iron is now my #1 choice. Coat it with Kroil and store it with VCI paper (which is more than I do), store in your air conditioned house, and wiper with isopropyl alcohol before casting. For long term storage, put it in a mason jar with clean motor oil.

[billmc2]

I started another thread where I asked about the length of the Lyman bullet that justindad pointed me to. JonB and Hick both responded with an old mold and a new mold. In the other thread you can see my math, if you care about that. Here's the link https://castboolits.gunloads.com/showthread.php?458660-Lyman-452374&p=5604930#post5604930

I mention in the other thread, as a result of the math, I feel much better with the OAL I came up with. The listing in the Lyman book, which justindad points out, also shows powder charges encompassing those I used. This makes me feel much more comfortable with what I am doing. I'm really not sure how I missed the listing that justindad mentioned, but I did. This was my very first time trying to work out a charge without having a published data source which met with my situation (it was there, I didn't see it). By working through all this, with all y'alls (new phrases I picked up by moving to Dixie) help, helps build confidence with my processes. It shows me I might be catching on to this.

[billmc2]

Since 'ole hit and run won't answer...

SEE stands for Secondary Explosion Effect. The term is used when a firearm blows up when using light charges of powder. This is why I mentioned to stay above the minimum charges from loading manuals.

The biggest issue with a SEE is that, so far, ballistics labs can't replicate it on demand. Sometimes it occurs, but most of the time it doesn't. Same conditions, same gun, same everything, but won't occur on enough of a regular basis.

As for it being your issue with the light loads of AA #5, no. That is just a case of not enough pressure to get a good burn. In this case it will usually leave unburned powder in the barrel.

{edit: forgot some links}:



https://reloadammo.com/light-loads-can-explode/

https://sportingshooter.com.au/ask-uncle-nick/secondary-explosion-effect-a-reality/

45_Colt

Did I just say I might be catching on to this stuff? What was I thinking. Never in my life would I ever have guessed that to little powder could blow up a gun. I still need to read the 2nd link you posted, but the first was scary enough.

Thanks 45_Colt.

[justindad]

I do believe AA#5 is way too fast to create the hypothesized SEE event. I once loaded True Blue so light in 9mm that the brass rolled out of the pistol and landed at my feet.

[charlie b]

If you really want to know, US Army Interior Ballistics manual :)

Yes, it is 'riveting' reading (for an inquisitive engineer :) ).

https://apps.dtic.mil/sti/pdfs/AD0462060.pdf

This mostly deals with artillery size stuff but all the theory is the same. The burn rate calculations are basically the same ones used for small caliber stuff.

[charlie b]

I've had an excursion before as well. Little less dramatic than the link posted above since the gun survived.

Mine was .45Colt, 255gn, and Blue Dot. But, it was a near max load. The difference was it was still a low density load. I also made the mistake of tilting the barrel down and then raising it to level to shoot.

Technically I would not call the kind of event linked to a detonation, rather an explosion. There is a difference. A detonation would have resulted in a lot of smaller shrapnel while an explosion kind of 'rips'/'splits' things apart as described in the link. Yes, to most people it doesn't make any difference, but, some of us it does. Kinda like the difference between magazines and clips :)