AR308 Feeding Problems

[Flux Capacitor]

Put together an Ar308 with a CMMG Mk3 lower, DPMS upper. I am having feeding problems. The rifle has problems with the last 3-4 rounds in the magazine. I have tried DPMS mags, and a 10/20Pmag.

The bolt catches the top round and starts pushing it forward but the cartridge ends on at an angle and the bolt smashes and bends the cartridge. I have a lot of bent cartidges!

So far, I have tried 2 DPMS mags, one Pmag 4 different types of ammo, polish feed ramps. Any other suggestions? I am starting to think its a POS

[G-forceJunkie]

So the bolt overrides the base of the brass then the two lugs on the bottom of the bolt gouge the heck out of the side of the brass, right? What ammo? What usually causes this is the rifle is short stroking, or the magazine feed lips are holding the cartrage at the wrong angle (usually too low) or the mag lips are not releasing the base of the cartrage soon enough or the mag spring does not have enough strength to get the last few rounds up in place fast enough.

[Flux Capacitor]

So the bolt overrides the base of the brass then the two lugs on the bottom of the bolt gouge the heck out of the side of the brass, right?

YES!.

I am using Federal Power Shok, handloads, PRVI and Winchester. WHats ur suggestion?

I don't know if short stroking would cause the last 3 or 4 in the mag to not properly be stripped by the bolt?

[ott1]

Have you tried it will 3 or 4 rds in the mag instead of fully loaded?

[Flux Capacitor]

Have you tried it will 3 or 4 rds in the mag instead of fully loaded?

Yes, same problem. Although I did notice that a few pieces of brass did not eject very far.

Actually does it (bends cases) while hand cycling

[G-forceJunkie]

Sounds like a weak mag spring. If the upper rounds are feeding fine, a weak mag spring showes up on the last few rounds. Basically the bolt is coming forward before the round has a chance to get lifted all the way up to the mag lips. Or the bolt pushes the case forward untill the bullet hits the feed ramp and the weak spring allowes the rear of the case to be pressed down, the bolt overides and jams up.

[ott1]

Maybe unrelated, what stock are you using? Fixed or retractable?

[mod1217]

I had the same problem and the first thing that came to mind was a weak mags spring but in my case like yours all my mags acted the same way I was at a lost.
Then I notice that the Bullet Button is somehow making my Magazine catch loose. At higher load the force of the magazine spring on the bullet pushing on the bolt makes it stable but as the ammo is spend it makes the magazine wobble and that was making the bolt catch the ammo in the wrong way causing misfeed.

But this happen on my AR-15 not on my LR-308 so it maybe a totally diff thing in your case but wouldnt hurt to check right

[Flux Capacitor]

I had the same problem and the first thing that came to mind was a weak mags spring but in my case like yours all my mags acted the same way I was at a lost.
Then I notice that the Bullet Button is somehow making my Magazine catch loose. At higher load the force of the magazine spring on the bullet pushing on the bolt makes it stable but as the ammo is spend it makes the magazine wobble and that was making the bolt catch the ammo in the wrong way causing misfeed.

But this happen on my AR-15 not on my LR-308 so it maybe a totally diff thing in your case but wouldnt hurt to check right

That sounds right. What was ur solution?

[Hoop]

Mag sitting too low, out of spec mags/lower receiver or your bullet button isn't making enough tension. You could try bending the feedlips of your DPMS mags up a bit so that the rounds sit just a little higher as well as tightening your bullet button down/take out the spring, stretch it a little and put it back together.

[mod1217]

That sounds right. What was ur solution?

At the range I use Masking tape at first to make the Magazine catch grip tight againts my mags. PROBLEM SOLVE. When I got home I just remove my bullet button and reinstall it making sure the spring is not bent or twisted in any way that solve my problem on my Pmags but my one and only steal magazines it is still a no go so I just use Pmags

[Hello Kitty Assassin]

If its the mag catch try getting an armalite one. They are longer and work better with the bullet button on the 308 lowers