I need some hand loading help.
This is long; I wish I could make it more succinct.
I purchased new Lapua brass because I was having a very hard time sizing .308 LC brass that I was shooting in a LaRue PredatOBR rifle. It turns out that several hand loaders have posted similar experiences when loading brass that was shot in a LaRue with their Xtraxn (tm) chamber. There are some work-arounds that I am pursuing.
The first hand load of the Lapua was pretty normal and I thought the problem might be solved but at the second loading the problem was fully back. Using a lot of force I was able to size the brass. I properly annealed it and checked each piece in a L.E. Wilson case gauge. So far, so good. All primers seated with the normal amount of tension and the bullets seated with a very consistent feel from the press.
I decided to put the LaRue away for a while and go back to an LMT that also shoots very accurately. I fired 50 rounds of the Lapua brass that had been twice fired in the LaRue in the LMT while performing an OCW test at relatively light loads between 42.8 and 45 grains of Varget under a 168 gr SMK, all at magazine length, 2.80”.
I was hopeful that the sizing problem was resolved as I have reloaded brass numerous times out of the LMT without issue. After tumbling in stainless steel media, sizing was much much easier—only a little more difficult than normal, possibly attributable to my recent switch to SS media.
When I dropped the cleaned case into the L.E. Wilson case gauge, I was surprised to see that the case head had not entered the gauge. Neither did the next or the next or then next…? I couldn’t force it in either. I tested inserting a primer just to see what what would happen and I could set the primer with my finger—no tool just my finger. I still had all of the primers from the cases prior to tumbling as I had cleaned the press prior to starting this next batch. They are all flattened and flared but not cratered. There are no burrs or swipes on the case heads. What a waste of great brass.
I used a Labradar on each round fired an there is no data that indicates overpressure. 42.8 gr shots were clocked at an average of 2612 FPS with a SD of 4.3 and 44.9 gr shots were clocked at an average of 2732 with an SD of 11.01.
Is it common knowledge that once you reload brass it should not be used in any other chamber, especially one semi-auto to another?
What do you make of this?
Thanks for your help,
|Knows too little |
about too much
Sounds like your F/L die was not screwed down enough to size the terminus of the case near the case head or to bump the shoulder back far enough. Of course, that doesn't solve the primer pocket issue.
The upper end of the load range sounds a bit hot to me, but I have run 175 SMK with 44.4 gr Varget out of my bolt rifle. However, i have little experience loading for a 7.62 gas gun. However, I have a set of Lapua brass subjected to the above loads and very few primer pockets have gotten too loose to use.
Hope you get it figured out.
It has been a somewhat disappointing day in reloading land for both of us. See my post above.
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Different chambers size will give you a different pressure. The reason we recommend workup loads for each gun. If they end up being the same good, but not always the case. I have a AR-15 with a min spec match chamber. I can take the fired brass from it and it will fit into my cheap Wydle chamber AR. Resizing it is way different, too. I anneal every cycle to make it easier to resize. If it's very hard to size I go to a point then remove and relube heavier. So far I'm getting good life out of my brass. My Lapula brass with 10 cycles will only hold #41 primers, all others are too lose for my liking.
You may want to check you OAL and see where your at on bullet jump. You can be at min and get over pressure signs if you into or to close. I prefer to be a min 0.020" off. And with the min spec chamber I find quite a few published OAL putting me into lands. I check max OAL with every different bullet I shoot. I've even had a lot of bullets that put me 0.005" closer than what I normally use. Does not hurt to spot check.
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RMD - There is something else wrong. Maybe I pushed the shoulder back to far. I believe I have seen flattened primers before as a result of too much cartridge head space. The one thing that I did differently to that brass was use a Dillon sizing die rather than the normal RCBS FL (not small base) sizing die I always use. I made that change because it is much faster getting a stuck cartridge out of a Dillon die than out of the RCBS die.
Maybe there is just too much going on with that brass to draw any useful conclusions.
Here are some conclusions that I have come to:
After brass has been fired, it will be dedicated to that gun exclusively.
I am going to try the one work around for the PredatOBR and see if that changes the resizing for the positive.
I am going to have to stockpile a lot more brass given the decision to assign brass to a specific rifle/chamber.
Thanks for the feedback and miser company. When I am shooting for the most accuracy I can get, I do weigh and sort bullets. I weigh each charge twice on separate scale too.
If you have a rifle with excessive head space and you size your brass correctly, it will stretch the case out everytime you fire and you'll get case head separation sooner or later. If you size the brass enough to fit that chamber and not stretch, it won't fit a case gauge or a "correct" rifle.
If you have any number of rifles correctly head spaced, you can use correctly FL sized cases in any and all of them.
Leade will have an effect on pressure but your loads should be fine in a correct rifle.
If I were going to try and figure out the source of your problem I would start by dropping whatever annealing process you are doing and set the dies up using your case gauge not any one rifle.
Then gather information from the ammunition fired from various rifles.
I don't think Larue changed dimensions with their "xtran" chamber it's just fluted like an HK or cetme but with a twist. Shouldn't make any difference other than cosmetic for reloading.
Pic too big for easy reading http://looserounds.files.wordp...2-05-10-13-36-24.jpg
This is easily explainable. The firing in that porky chamber allowed the case base to expand more than usual. One possible remedy for that is the use of a small base die. This die is designed to bring in the OD at the base of the cartridge more than a regular die does, hence the name "small base".
The brass is thickest at that portion of the case and sizing it back will require a vigorous push on the handle. Doing it with a small base die will be even worse.
The problem is that once that portion is enlarged, it is near impossible to push it back in, small base die or not. I had to give up a whole batch of fairly new Lapua brass when I changed the barrel in my F-TR AR-15 from its Wylde chamber to a Krieger 5.56 NATO Match chamber (much tighter.) The case would not even fit in a guage.
When the base expands, it also allows the primer pocket to expand, of course and that's when the brass expires.
I use a small base die for my .308 loads from the first firing. The brass requires no special push to resize and the primer pockets last longer. My loads are much stouter than your weak loads (not even max, according to Hodgdon website.)
Live and learn.
Thank you NikonUser. That makes a lot of sense! I do have some questions.
Question 1: What I write next only applies to my LaRue with the porky Xtraxn (tm) chamber. One relatively widely but unofficially accepted remedy is to get a full length die from Forster where the neck is reamed to .3320. That does not sound anything like your suggestion. Perhaps if one only runs brass in the LaRue this makes more sense? Pretty sure you are going to say no.
Question 2: Having never used small base dies, is the only difference between it and a FL die the dimensional change at or near the base? The real question is will using a small base die negatively impact the sealing of the case to the chamber wall in the semi-autos I like to shoot?
Question 3: This is not a complaint. If my chamber IS porky then the small base die will work the brass even more than the FL die right? The case will expand more than we would optimally want and the SB die will size it smaller than we need. If this increased the firings from 3 to 6 or 8, I would be happier. Is the goal with the SB die in this application to size smaller than the FL die and though the case base is going to expand it will not expand dimensionally as much as it would have if sized in a FL die?
Question 4: Hope this isn’t too boring. If it is the base and the head that are over expanding, isn’t that really a problem with the bolt rather than the chamber? When I look at how a case is held in a semi-auto, there is a lot of base outside the chamber that, once closed, the bolt surrounds.
If I understand you what I gather is there is a reason your brass is stretching.
Powder could have a bad lot.
Your weights might be off ,scales might be adding a few more grains.
I have hand loaded for over fifty years ,mostly 06 and shot thru a dozen or more guns without any problem.
Your powder I dropped thirty years back as it was all over the place with velocity when my croni worked.
I never could spring for your brass but always bought new winchester brass.mostly use pickup O P brass.
Shooting I did a lot,that 20# black keg lasted three years of IMR 4350 back in the late sixties.
Not saying this is but could be worth looking at.
Wow, you're full of questions, aren't you? Let's see if I can answer them properly.
You are correct, that Forster die has nothing to do with my suggestion, and you can do the same of better with a bushing die where you select the bushing to match the brass you have. For my Lapua brass, I use a .335 or .336 bushing (I can't remember now,) and it gives me .002 of neck tension. Using a .332 bushing would give me .005 or .006 of neck tension. That's what holds the bullet in the case.
What I'm talking about is a small base die which will squeeze the base of the brass, just above the extraction groove a little more than a regular die.
The use of the small die is indicated for semis, which tend to have more generous chambers and less bolt-closing force compared to a bolt or other actions. If the case is a little oversize, a semi can jam or not lock. You don't want that. Yes, the difference between regular and small base is at the bottom, the base. As for obturation (the proper term for sealing a chamber,) if you use a case guage, you will notice that factory ammo will slide in nicely, as do my multi-times fired brass; they are at SAAMI-specs. The SAAMI-spec case will obturate just fine; it did the first time you fired that brass in that chamber.
The military is very fond of porky chambers because they don't reload and lots of vendors do the same, thinking Mil-spec is the best. Ijiots.
Who knows? Did you measure the OD just above the extraction groove on a virgin case and then on the fired brass? I'll bet the difference will be more than .003, probably a lot more. You can either decide to us a much lighter load, dedicate that brass to that rifle only and continue with the regular die or buy and use factory ammo only. A small base die WILL be more work at resizing time but it MAY increase the life of your brass.
I am not familiar with the LaRue PredatOBR rifle. So I went looking on the web. That's an AR-style .308. If it's anything like my AR-10B (T) and all the AR-15s I've ever played with the bolt in the BCG only hold the face of the case up to the extraction groove. The rest of the case, from above the extraction groove on up fits inside the chamber completely. The bolt face on the bolt will be a little loosy-goosey, but that should be like your shellholder, it's not going to resize or allow to expand that area; that's all on the chamber of the barrel.
You're very welcome.
Thank you professor NikonUser. Excellent lecture for me today--and it's all about me right?
One more question?
I would like to neck size but as I almost exclusively shoot semi-autos I want to understand how I would do that correctly.
It sounds like one workable strategy would be to get a small base die with the neck reamed to a slightly wider diameter than the sizing bushing that I want to use because I still need to push the shoulder back and more than the two thousandths that you do with your bolt guns.
The Internet says for a semi-auto, one should push the shoulder back three to five thousandths (maybe you don't agree with that)?
After sizing with the SB die with the reamed neck, I would bushing size the neck. My reason for desiring to to this is to stop pulling the expander ball through the neck and the distortion that causes to the neck and shoulder likely resulting in worsened concentricity of the case.
Is that roughly correct?
Thank you in advance again,
P.S. There are other good posts here and I don't mean to ignore them but my shooting is reasonably well instrumented and I am not shooting in the upper charge ranges of the powder. Each and every shot is tracked by the Labradar chronograph and the SDs are 11 and under with many of them in the low single digits. Further, the velocities are what I would expect using that powder and my 20" barrel. There are no visible pressure signs on the case like swipes or burrs AND I had none (zero) of these problems before adding the LaRue rifle with its unique chamber to the mix. This is a learning experience for me and while the simple solution is to rebarrel the LaRue or get rid of it all together, as hand loaders, we have already chosen the more difficult route. I want to see this through to the end and once I fully understand the issue and what, if anything, can be done to minimize or eliminate the brass destruction then I'll decide if it is worth the extra gear, effort and care to MAKE it work. More than anything, I plan to continue hand loading and while I hope to not see this issue again, I do want to understand it as I think my issue may be closer to the extreme; I don't think this is an edge case that I will never see shades of again.
^^ It sounds like you want to use a body die first, and then use a Type S die in a separate operation. You shouldn't need to ream out a FL die when you can just get a body die from Redding.
The man never stops asking questions. I'm happy to oblige, however, because I like to write and this is a fun subject.
Sure. Yes, it's all about you.
The internet says a lot of things; I'm just another voice. The first thing you should look into is something called a body die. This is a die designed for the idiots (sorry, I meant the nice people) who think that for some reason neck sizing is better than F/L sizing. The body die, which can be had in small base, will resize the body of the die and reduce the shoulder also, but will leave the neck alone. The ijits neck sizers will neck size for a few cycles and then when the body gets too big and extraction or chambering becomes difficult, they use a body die to return the case to near virgin dimensions and neck size a few more times and then use the body die again. These ijits seem to think this gives them more consistent ammo. They are, of course, very wrong. Look at it this way: tell me how a case which has just been body sized and then neck sized anywhere close to the prior use when the body was getting so big you could hardly extract the case?
Competitors or at least the serious ones, prize consistency in ammo above everything else. After the first firing, I use a F/L small base bushing die to resize my brass, adjusted to push the shoulder back right about .0015 from fired dimension, on the average. This is very small in expansion terms, and lends itself well to long case life. If you resize your brass and push it back more than that, it will grow again at the next firing and that will weaken the case about a quarter inch up from the extractor groove. Do that several times and you have case head separation.
Story time. We have a guy on the team who recently got a new barrel and a new press. Last weekend, he had several misfires during the team match. Upon investigation, we discovered that he had adjusted his sizing die incorrectly in his new press and had pushed back the shoulder about .010 instead of .001. When the firing pin would hit the cartridge it would simply seat it further in and not detonate the primer, but create a small indentation. What a pain. He even had one that when it was extracted it was coming apart at that spot I mentioned earlier. He had to throw out all the brass that he had resized.
If you handload for a specific rifle, I would never push back the shoulder much more than .002 or .003. But here's the problem. If you reload for several rifles, then SAAMI specs are your bible. What you want to do is resize the brass so that the shoulder matches the shoulder of a virgin case or a factory loaded cartridge. They are at SAAMI, they have to be in order to be useable in any rifle of that chambering.
NEVER, EVER GO BELOW SAAMI SPECS when resizing. Read that sentence again.
People who resize virgin brass are asking for trouble because it's already at SAAMI specs; people who aggressively push back the shoulders below SAAMI specs are also looking for trouble. So unless you know EXACTLY what you are doing, observe SAAMI specs when resizing and loading and you'll be fine.
I am not aware of a single high-level F-class competitor who neck sizes and I seriously doubt anyone who handloads for PRS would do that either. The folks who are most likely to neck size are benchresters but they have very specific reasons to do that and they have their own regimen for loading. They will prepare 10 or 20 cases and care for them more than their family and use them over and over again. I have 500 cases in rotation for my barrel and they are all interchangeable because they are all F/L small base resized after every firing as described in my thread above here.
As for the expander ball, if you use a bushing die with the proper size bushing, there is no need for the extractor ball, just remove it from the stem of the die. I use my resizing die to punch out the spent primer but it does not have an expander ball.
Are you saying that I can use a good FL SB sizing die, remove the expander ball, set the die to push the shoulder back to SAAMI spec or some length longer (not shorter) than spec that will reliably cycle in my rifle(s) and that is it for sizing?
I think you are going to tell me "not quite;" that I need to measure the specific case when loaded or have a good understanding of the neck thickness of the brass I use and therefore the loaded diameter in order to have the FL SB die reamed to some dimension that is in the neighborhood of .002” less in the neck.
Is that right-ish?
Thank you for the education—really. I am some sort of idjit but I desire not to be.
Yeah, pretty much. That's all I ever do to my match brass when it comes to sizing. Read the rest of my thread above to learn about annealing, trimming, etc, but for me decapping and sizing is one operation and the case goes into the tumbler. Please note that I have the exact bushing for that die. It must be a bushing die. I use the Redding S-type bushing die.
Also, please note that I leave the case full up in the sizing die for a second or two, not just go down/up. I give the brass a chance to get to its size; to minimize spring back.
The bushing is the secret here. The Redding S-type die (there are other brands,) needs to have the proper bushing for the neck to be sized properly. For .308 Lapua brass, I use a .335 or .336 bushing. For Winchester brass, I use a .331 bushing. The Winchester brass is thinner than the Lapua brass.
Order the proper bushing for your brass.
Got it! Thank you. I have read your hand loading thread in its entirety numerous times. It is very informative and has greatly accelerated my hand loading knowledge and skill.
I have come to realize that hand loading has many more facets than I previously thought or imagined. It does take time, direct experience and dedication though to build the personal knowledge and experience if you want to build more than just ammo to shoot. I do.
You have done a great job of giving relatively new hand loaders (5 years for me) some large blocks of knowledge that we can use to improve our process immediately and a lot of equipment and process to aspire to.
Thank you again,
You're very welcome. This was a good thread.
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