Took my DPS LR-308 out today to sight in my new scope and had some ammunition problems. I dont have access to any match grade ammo atm so I had to use what I could find at Walmart. I picked up a box of Win powermax to sight it in and some cheap fedral power shock to plink with. About 1 in 4 shots with the Win ammo, the primer blew out and jammed the bolt. I have never seen this before but this is my first autoloading rifle. Surprisingly the cheap Fedral ammo fed and fired perfect. Its not consistantly accurate but at least it was not blowing apart in the chamber. Attached some pictures of the aftermath of both casings so that maybe someone can advise me. Not sure if its the ammo or if something like the gasblock needs adj for that specific ammo. Thanks in advance!
What caused this?...LR-308/ammo question
- Thread starter JDTech
- Start date
rezmedic54
New member
Bad Cases
I had this problem a few months ago with some Privi .308 ammo. First thing we thought was head space but that was not it. Turned out to be some bad cases the primer pockets were almost over sized to start with so when they where lit off it was just enough to finish stretching out the pockets. You may have got some of that bad brass.
I had this problem a few months ago with some Privi .308 ammo. First thing we thought was head space but that was not it. Turned out to be some bad cases the primer pockets were almost over sized to start with so when they where lit off it was just enough to finish stretching out the pockets. You may have got some of that bad brass.
I'm quite happy with my DPMS LR .308 L.I would like for the DPMS bashers to show me some inspection reports for non conforming parts.
Did you run a patch through your bore to make sure it had no anti-rust grease in it?That would raise pressure.Something like a 180 hunting bullet may have driven into the rifling,that could be a problem.The bores get the same oxide treatment as the outside of the barrel.it can be a bit toothy the first several rounds,that can raise pressure.
Is the WW Powermax some super performance ammo that may have a long pressure curve?While aftermarket adjustable gas blocks may be available,probably you don't need them.When ammo like Hornady superformance gets more velocity without raising peak pressure,they lengthen the peak pressure curve.Are the pockets blown way oversize,or did the primers blow out due to residual pressure after the rifle unlocked?Is this a carbine with a short gas tube?Even the fine,reliable,venerable Garand can be damaged and taken out of action by firing bolt gun safe 180 gr hunting loadswith slow powder.Gas operation requires proper ammo.
WW has increased the sensitivity on their primers and they may be less suitable given the floating firing pin.BTW,Armalite has a firing pin retraction spring,DPMS does not.
if any primers pierced,the cookie and some crud went inside the bolt.Disassemble it,clean and lube.If the ejector works in and out smoothly,you may want to leave it in place,same with the extractor little roll pins,springs,etc.
Frankly,high quality handloads are the practical solution to feeding an AR in 308
Did you run a patch through your bore to make sure it had no anti-rust grease in it?That would raise pressure.Something like a 180 hunting bullet may have driven into the rifling,that could be a problem.The bores get the same oxide treatment as the outside of the barrel.it can be a bit toothy the first several rounds,that can raise pressure.
Is the WW Powermax some super performance ammo that may have a long pressure curve?While aftermarket adjustable gas blocks may be available,probably you don't need them.When ammo like Hornady superformance gets more velocity without raising peak pressure,they lengthen the peak pressure curve.Are the pockets blown way oversize,or did the primers blow out due to residual pressure after the rifle unlocked?Is this a carbine with a short gas tube?Even the fine,reliable,venerable Garand can be damaged and taken out of action by firing bolt gun safe 180 gr hunting loadswith slow powder.Gas operation requires proper ammo.
WW has increased the sensitivity on their primers and they may be less suitable given the floating firing pin.BTW,Armalite has a firing pin retraction spring,DPMS does not.
if any primers pierced,the cookie and some crud went inside the bolt.Disassemble it,clean and lube.If the ejector works in and out smoothly,you may want to leave it in place,same with the extractor little roll pins,springs,etc.
Frankly,high quality handloads are the practical solution to feeding an AR in 308
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I thought it might be as well, but from looking at Winchesters web site it is just a standard .308 with a velocity of 2500 fps at 100 yards. Winchester states this is ammo designed for the White Tail hunter, using a bonded core bullet. Nothing like the Hornady Superformance or Light Magnum ammunition that were pushing the pressure limits.
Did you shoot all the ammunition? When you have something like this happen contact the manufacturer and file a complaint. Usually they will ask for the unfired ammunition to be returned and they will credit you the purchase price or send you a new box to shoot.
The rifle has the the 24" SS fluted bull barrel. I had put one box of WW White box through it before this trip and I cleaned it good before and after that. I had no problems with any of those. And yes the shoulder is warped from the extracter ans the casings seem to be pretty scratched, not sure if that's normal from extraction. They were both 150gr loads. Out of 15 casings I recovered 7 are blow out and all but 1 have a black ring around the primer from leaking gas. Adding a pic of this.
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riverwalker76
New member
Win Powermax is intended for hunting purposes, and is not everyday plinking ammo. It is loaded to a little on the MAX side for optimal energy and speed.
I wouldn't shoot Powermax in your LR-308 very often. It tends to be a little hot for the gas guns.
The only thing I could figure on the case blemishes .... the timing on your bolt blowback is off. Do you have an adjustable gas block, or is it standard?
I wouldn't shoot Powermax in your LR-308 very often. It tends to be a little hot for the gas guns.
The only thing I could figure on the case blemishes .... the timing on your bolt blowback is off. Do you have an adjustable gas block, or is it standard?
The temp was a wonderful 70deg and sunny...awsome for kansas in January...and the reason we were out....I got the power max because i wanted something closer to match grade for sighting in my scope.....What then defines "match grade" other than those words on the box?? And I believe it came with the upgraded adj gas block but will have to double check on that. If it just the hot loads then I just wont buy them anymore 
StrongSideArmsInc
New member
What was the grains of the bullet, you are not supposed to shoot anything over 175 grn out of the DPMS LR308 models. To much pressure, that could cause primer flow, which, from the picture that is what it appears to have happen.
StrongSideArmsInc
New member
I saw that they were 150 grn loads, inn the previous post, something to do with the ammo. If it was the gun, it would have done it with both loads.
Last week, a customer bought some Remington 150gr 308 wins from Walmart, which caused a squib load. he brought the gun in for me to take the bullet out. He also brought the the ammo in too. I pulled the remaining bullets left in the box, and three of the bullets had no powder in them. A phone call was made to remington.
I heard Walmart sells factory seconds, I DO NOT KNOW IF THATS TRUE, but this sure does appear good.
Last week, a customer bought some Remington 150gr 308 wins from Walmart, which caused a squib load. he brought the gun in for me to take the bullet out. He also brought the the ammo in too. I pulled the remaining bullets left in the box, and three of the bullets had no powder in them. A phone call was made to remington.
I heard Walmart sells factory seconds, I DO NOT KNOW IF THATS TRUE, but this sure does appear good.
riverwalker76
New member
taylorce1 said:
Max pressures in a bolt gun are different from those in a gas gun.
If it were my rifle ... I'd stay away from commercial hunting ammo altogether.
Also, just because Winchester doesn't admit to it being a MAX load ... doesn't make it so. I've known them to push the limit with a lot of their factory ammo. A perfect example is their .223 Federal 55gr. FMJ ammo. It is loaded beyond what most reloading data manuals would consider to be safe. I've seen pressure signs out of every other cartridge during most plinking sessions.
bigalshootmupper
New member
Do you have any of the ammo left? I'd call Winchester and tell them what happened. Sounds like the ammo has very loose primer pockets and the case is rocketing itself out of the bolt. I reload and notice a big difference in primer pressure into the primer pocket when loading the primers. Never had one do that though.
I've got the same LR-308 and never had a problem. I did have one punctured primer on a factory Fed powershok 150gr. That's the only problem out of about 700 rounds.
I've got the same LR-308 and never had a problem. I did have one punctured primer on a factory Fed powershok 150gr. That's the only problem out of about 700 rounds.
SadistAssassin
New member
the only ammo my lr 308 has ever seen is that cheap federal 150 grain stuff, never had a problem in 400 rounds or so
It is a .308 rifle not a 7.62X51, hence the DPMS LR-308 not LR-7.62. This gas gun is built to handle the same pressure levels as a bolt gun in the same chambering. That is why it should be able to shoot the ammunitinon, and I say 2500 fps at 100 yards is no where near max pressure for either type of rifle.
Best I can tell the Win PM should have a muzzle veloicity around 2850 fps which is the same as the 155 grain Match ammunition offered by Hornady. Plus it seems checking Federal and Hornady's web sites seems 150 grains with a MV around 2850 is pretty much the standard. So if the match ammo and hunting ammo runs at that speed I don't know where he is going to find something that opperates at lower pressures.
I'm sure there is an ammunition problem here, with this box of ammunition. I wouldn't say that he is going to run into this problem if he uses it every time. This is why I said he shouldn't have shot it after the first time he had a primer blow. That way he could have sent the ammunition back to Winchester so the ammunition could have been pulled apart and the problem found.
madcratebuilder
New member
Have you checked the head space? That would be the first thing to do. 7.62 head spaces a few thousandth different than .308, be sure and use the correct gauges for your chamber.