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Old May 26, 2019, 12:30 PM   #1
Old 454
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Dpms LR308 Buffers

How heavy of a buffer do you all run in your AR10 308.

Mine is 3 5/8 OZ. & 2.525 inches long. And I get a few light primer striked.
Checked my chamber with the hornady oal length chamber checker and got 2.804 in a Noreen AR10
I seat my bullets 150 grain fmjbt to 2.795
I also have gotten a few light primer strikes with commercial ammo.. PPU and American Eagle.
I think I may need a heavier buffer.

Any help and opinions are greatly appreciated

Thank you in.advance

Last edited by Old 454; May 26, 2019 at 12:35 PM.
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Old May 26, 2019, 02:52 PM   #2
riffraff
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I have a few Aero and a S&W, run both the standard and one has a 5.3 ounce and sprinco orange to counteract over gassing - but as far as I know its got nothing to do with primer strikes..

If your headspace is ok (and I only check that with my gauge no idea on actual measurements) would seem you most likely got a firing pin, trigger, or ammo thing.

Light strikes are not a problem Ive seen and thats across lots of brass case factory ammo, not picky about it I just buy whatever is cheap. If you messed with the trigger Id start there.
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Old May 26, 2019, 04:20 PM   #3
Old 454
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No never touched my trigger. As a matter of fact have not changed or adjusted any thing

Gun Smith head space is fine.

I guess what I forgot to mention is when I get a light strike I notice that bcg does not go fully into battery and I get a light strike so I was thinking heavier buffer more mass to push the bcg fully into battery
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Old May 26, 2019, 06:57 PM   #4
Mobuck
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"I also have gotten a few light primer strikes with commercial ammo.. PPU and American Eagle.
I think I may need a heavier buffer."

Why do you think that?
Buffer weight really has nothing to do with light primer strikes although the impetus from a heavier might(?) slam the bolt closed very slightly harder. If chambering is a problem, that needs to be addressed with cleaning, polishing, or some other mechanical means.
Overly light hammer spring might be the primary cause.
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Old May 27, 2019, 12:10 PM   #5
riffraff
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Really your problem is not going into battery consistently. One of the guys here taught me this: holding the upper at a 45 degree angle the bcg should slide into battery under its own weight..

First make sure you dont have a piece of brass fouling things up, look around the chamber good with a light. Make sure your bolt moves well inside the carrier - lack of proper cleaning can make things real sticky there, you gotta clean the inside of the carrier where the bolt rides as they can have buildup in the bottom..

Even the gas tube or key can be at fault.

And of course the lugs all gotta work well together, but 1st Id check the other stuff if you have been shooting the rifle regularly and it worked well before but not now.
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Old May 28, 2019, 07:25 PM   #6
Jsnake711
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I use a 3.8 but with an adjustable gas block. But it sounds like you have another issue.
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Old May 28, 2019, 09:38 PM   #7
bfoosh006
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How many rounds fired through your 308 AR ?

It might need a little more break in.

I also don't think a heavier buffer weight would aid positive hammer strikes.

I would check / cleanmyour firing pin channel through the Bolt... if you have had a pierced primer, it might be binding at your firing pin.

Also, as silly as it sounds, check that your firing pin is properly made.

I had a 308 FP that did not have the collar to shank edge "squared" off... it was slightly radius'd , enough so that it interfered , contact wise, with the FP retaining "cotter" pin.

Eventually, the bad, non-squared off FP bent the heck out of the "cotter" key.

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Old May 29, 2019, 06:36 PM   #8
Old 454
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I noticed that cotter pin that retain the firing pin has a slight bend in it... I will replace that.
I also order a new Trigger .. the Rock River arms 2 stage Match trigger.
I am also going to order heavier hammer springs.

I do load all my own ammo... but I shot about 100 rounds of commercial ammo.
I bought 500 brand new pieces of star line brass.
Changed out my loading dies from Lee to Dillon dies.
I did have the AR10 checked by a gun Smith at Copper Custom
They checked the head spacing and also polished the feed ramps and lapped the chamber and polished the bore
They told me head spacing was good and stated they ran a box of military ball and a box of unspecified commercial ammo and told me no problem
I bought a hornady OAL guage and measured 2.804 for my OAL for chamber

I believe I might have a very tight chamber ... may wind up buy a new barrel or upper
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Old May 30, 2019, 06:06 AM   #9
Mobuck
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Sounds like you've been chasing a ghost through the bushes.
If the rifle worked with factory ammo and has this problem with your reloaded ammo, that's an indicator.
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Old May 30, 2019, 06:49 AM   #10
Old 454
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No there was light primer strikes and failor to go into battery and a few stuck unfired cases.

When I changed out my dies on my press from Lee dies to Dillon dies and Dillon dies are small base full length dies the stuck case problem went away.

So along with the trigger group I bought I just also bought a 800 grit Flex Hone chamber hone and honing oil i read up on this and people that had same problem as mine stated using the flex hone alleviated there problems that were caused buy tight chamber.

The more i have been reading up on this it looks like dpms 308 rifles tight chambers is some what common.

I will give range report this coming saturday
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Old June 2, 2019, 03:08 PM   #11
Old 454
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Well took the 308 to the range... ran much better but still need to work a bit more on the chamber.

So I will hone the chamber a bit more and back to the range next saturday
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