Problem with LR 308

Scott · Sep 23, 2009

Bought LR 308F about 3 weeks ago and waited long time to get it. Just pulled out of safe to take to range. Started cleaning bcg and finished and thought would finish the rest tomorrow. I heard about all of the feeding and ejecting problems as well so I thought that I had just a little time left I would manually cycle 5 rounds in the mag to see if any would jam. DPMS told me I might be able to tell that way. Anyways I put 5 rounds of Federal 180's soft point and cycled them and they fed and ejected well. The problem is when I picked them up off the ground I noticed the lead tips were smashed and the bullet and case had scrape marks as well and then I looked at the primers and they had dents that looked like misfires as well. So I tried Hornady Tap rounds and the tips were ok but the bullets had the scrapes as well and the primers looked like misfires. Again I was worried that a slam fire was about to happen so stopped. I was in a safe location so I am safety conscious. Anybody ever see this? This is a brand new gun and I don't know how they leave the factory like this. I feel this is a serious issue because if the mag was full and slamfired could be very dangerous. I am upset that this happeded because I have an expensive paperweight in the mean time. Thanks for any comments or suggestions. And yes I am calling DPMS tomorrow. :nuts::angry: :s0092:

huntpotter · Sep 23, 2009

I only shoot Mil-Spec 150gr FMJ, out of my M1A, AR-10, and Fn-Fal. No problems. No jams. South African surplus battlepack stuff works great. Federal American Eagle works great. Federal Gold Medal Match 168gr hpbt works great too, just too spendy to shoot. I think that 180gr soft point stuff is made for a hunting bolt action. Also mil spec stuff has a harder primer, so you won't have any problems with the firing pin denting the primer. It has to hit hard to go bang.

eldbillbo · Sep 23, 2009

thats really strange there should be no way that the firing pin should be able to touch primers expessially hard enough to dent them i undestand the soft lead problem i had that issue with my grendel

is the firing pin bound up in any way and when you push the bolt back does the pin recess all the way into the hole? if you shake it does the pin move freely ?

Scott · Sep 23, 2009

eldbillbo said:
thats really strange there should be no way that the firing pin should be able to touch primers expessially hard enough to dent them i undestand the soft lead problem i had that issue with my grendel

is the firing pin bound up in any way and when you push the bolt back does the pin recess all the way into the hole? if you shake it does the pin move freely ?

The pin is ok and the bolt slides back and fourth ok and the pin is secure. I don't know how it is hitting primers though. I have never seen this before. Could the firing pin be a little long? This just sucks. Plus it must be hitting the feed ramp at the wrong angle or something as well because it leaves little gouges in the bullet and case.

eldbillbo · Sep 23, 2009

when you push the bolt all the back does the pin stick out any?

in order to have pin strikes the pin has to be too long or binding up it should be totally loose and moving freely

the gouges in the lead may just be soft point issue . although these are great to hunt with the ar15 type rifles were not designed for soft points

like mentioned i used a grendel for hunting and it chewed up soft points and had feed issues so bad it was shoving bullets back into the cases but did not with FMJ ammo

i've not shot many soft points through a 15 but i tried some and had feed issues and dented lead with the ar i shot them through

the big issue (provided that its feeding even with dents) is the dented primers

some of the scrapes depending on how bad could be in part to it being new every thing is tight all the edges are sharp on the lugs over time the edges do ware and feeding becomes smoother

eldbillbo · Sep 23, 2009

also how deep are the dings

NoAim · Sep 23, 2009

Settle down guys. This is normal.

Let me try to shed light on your 3 problems: primer dents, scraped cases/bullets, and smashed softpoints.

Problem 1: Dented primers. This is COMMON and NORMAL with an AR type rifle. Most AR-15s and LR308s (AR-10s and some pistol cal versions are different) have a free floating firing pin. The act of letting the bolt slam forward allows the lightweight firing pin to also poke a little through the hole and lightly dent the primer. There is not enough force to set off a primer. If you are concerned about it, you can look at a spring loaded firing pin (although you may have light primer strikes and fail to fires unless you beef up the hammer spring or lighten the hammer weight), and always point it in a safe direction.

Problem 2: Scraped cases/bullets. You are ejecting a still loaded round. When the bolt is pulled back, the spring loaded ejector in the bolt face pushes the tip of the round against the bolt extension lugs. This causes scraping. If you want to test this, eject the round slowly, and push on the case, keeping it in the upper receiver until it has cleared the lugs.

Problem 3: Smashed soft point tips. This is due to the feed design of the AR series. It's not a bolt action. The bolt comes back, then moves forward. As it moves forward it catches the back of the round in the magazine and pushes it forward. The geometry of the feed then pushes it against the upper receiver/feedramps and it slides in the chamber. If the tip is very soft, it will deform when it hits the feedramps. The AR-10 uses a different geometry to fix this, but the AR-15, LR-308 and SR-25 types do not. The only fix for this is to use a harder softpoint or a different type of bullet.

MEP1000 · Sep 25, 2009

NoAim said:
Settle down guys. This is normal.

Let me try to shed light on your 3 problems: primer dents, scraped cases/bullets, and smashed softpoints.

Problem 1: Dented primers. This is COMMON and NORMAL with an AR type rifle. Most AR-15s and LR308s (AR-10s and some pistol cal versions are different) have a free floating firing pin. The act of letting the bolt slam forward allows the lightweight firing pin to also poke a little through the hole and lightly dent the primer. There is not enough force to set off a primer. If you are concerned about it, you can look at a spring loaded firing pin (although you may have light primer strikes and fail to fires unless you beef up the hammer spring or lighten the hammer weight), and always point it in a safe direction.

Problem 2: Scraped cases/bullets. You are ejecting a still loaded round. When the bolt is pulled back, the spring loaded ejector in the bolt face pushes the tip of the round against the bolt extension lugs. This causes scraping. If you want to test this, eject the round slowly, and push on the case, keeping it in the upper receiver until it has cleared the lugs.

Problem 3: Smashed soft point tips. This is due to the feed design of the AR series. It's not a bolt action. The bolt comes back, then moves forward. As it moves forward it catches the back of the round in the magazine and pushes it forward. The geometry of the feed then pushes it against the upper receiver/feedramps and it slides in the chamber. If the tip is very soft, it will deform when it hits the feedramps. The AR-10 uses a different geometry to fix this, but the AR-15, LR-308 and SR-25 types do not. The only fix for this is to use a harder softpoint or a different type of bullet.

+1 Well said NoAim

Gunner3456 · Sep 25, 2009

OK, slightly off topic but I hope related.

Has anyone tried hollow point (metal jacket) bullets to see if they will deform in either AR-15 or .308?

Is that a viable alternative to soft point for animals?

Thanks.

eldbillbo · Oct 4, 2009

Gunner3456 said:
OK, slightly off topic but I hope related.

Has anyone tried hollow point (metal jacket) bullets to see if they will deform in either AR-15 or .308?

Is that a viable alternative to soft point for animals?

Thanks.

are you talking about wolf hollow points ? no they don't deform but those are fine for varmints but for big game spend the extra cash and check out ballistic tip bullets if your ar or clone is having issues with soft tips

btw i shot 30 rds of federal soft point through a Lr308 a few days ago and had no issues what so ever and was shooting some tight groups with it