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I have been reloading for a while now, but I have a new rifle that is giving me fits...DPMS LR308. I ran 20 cheap Federal factory loads through it and the primers were flattened...I chalked it up to cheap loads...I have since started reloading the .308. I with an average of minimums from Lyman, Hornady,& Hogdons just to be safe. I also used the longest COAL between the three manuals.The primers were again flattened and a few were pierced. I went to 75% of max load on the rather conservative Lyman manual and still blown or flattened primers....I am using IMR4895 with 168gr Hornady Match, OAL=2.80, case trimmed to 2.008. What could it be? I already made sure I wasn't crimping to eliminate variables.I also make sure neck tension/thickness is consistent between batches... I'm at a loss...the only other thing is maybe crap primers? I am using Winchester WLR, but I also pulled from another stash of same make primers....maybe try on with a harder cup?.....could it be the chamber in the gun?....I'm at a loss....I have loaded a ton .223, 270, & 30-06 and have never run into this before....
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Is the chamber oil free? Oil in the chamber or on the cases can raise pressures.When asked what qualities he most valued in his generals, Napoleon said, "give me lucky ones." -
You "used the the longest COAL between the three manuals". Are you jamming the bullets into the lands? Typically you can't on a factory chambered gun but I've seen stranger things happen.Frank
One rifle, one planet, Holland's 375
Life Member NRA, CRPA and SAFComment
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I've seen the same thing on my DPMS 18" SASS LR-308 upper with reloads that I was working up using WC846. I started 10% below max and was blowing primers. I'll be going 20% down next.sigpic
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possible headspace issue?Comment
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^^This is where I'd be looking.
You went max COL perhaps out of concern for pressure but could be creating that very problem by stuffing a bullet right up in the throat. Why don't you try black smoking the bullet with no neck pressure at the case mouth and determine your maximum COL potential, then start backing off that. Are you familiar with that process? This will give you a good comparison to determine if there is a headspace issue, too.Last edited by Grizzled Bastard; 12-30-2012, 8:05 PM.Comment
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actually I think you will be going about 25 fps faster for every 0.05" deeper seating and you will raise the peak pressure by about 2,000 psi for each 0.05". If your load is 41.0g IMR 4895, you are at 100% capacity if you seat down to 2.70" and will start compressing if you go shorter.
You're sure you are loading to IMR4895 and not H4895 right? They are slightly different, but still, there is a difference.Comment
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Gas guns run different than bolt guns. I've owned and reloaded for a Knight's SR-25 since 1993. I have to use medium burning powders and cannot run it as hot as a bolt gun, usually 3-2 grains less. I tried some CFE 223 recently and blew primers. It does not have an adjustable gas block.
This rifle beats the brass. I've put in a Tubbs buffer spring and a CWS (Carrier Weight System) which has helped. With Federal Brass, I may get only 2 reloadings out of them. I get better results with Remington, Winchester and Hornady brass, but the brass still gets beaten.
You may be experiencing the same thing with your rifle. Try dropping your powders charges a bit and try some different primers, it may help.Last edited by FLIGHT762; 12-30-2012, 9:18 PM.Comment
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Have you tried it? I did the testing for the CA Service Rifle Team. What I said is true. How/why, I don't know. But I have fired thousands and thousands of rounds over a chronograph. It kind of makes sense though. When a bullet is jammed, pressures go up. As you seat the bullet deeper, pressures go down. Is there a limit to this rule? I don't know, but up to .250+" of bullet jump and pressures don't go up. Sometime I will post some targets with the load data on them. Some of the charge weights might give some here a heart attack.
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