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New LR 308 build problems


05titanle

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This going to be hard to explain. I guess you would call it a failure to feed problem. The bolt will start the case out of the mag then the bolt will not feed stright into the bore. The bolt will ride over top the case and jam it at a 45 degree angle. Need Help

welcome to the forum from southern wi

 

what blue said details plz

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Does it jam on every shot after that first ten each time you load the mag?

 How many rounds through the rifle? Are you using enough lube to make it drip out the mag well? You should break it in dripping wet with a good lube.

Have you tried different mags?

Will it lock back on an empty mag when only one round is loaded?

Is it possible it is short stroking and picking up the round with the carrier instead of the bolt?

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Had serious feed problems with the Ares Armor NIB BCG.  If you have access to and alternative BCG, giving that a quick try might just quickly define the problem.  Never found out what exactly was "out of spec", but a change of BCG got mine running perfectly.

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Welcome from AZ! 

Need a few more specifics , like is it new ? 

If so ... Rack the BCG About 100 times with some lube on it to mesh the upper to the bcg.

When you go out next time take a DPMS metal mag with you and a different kind of ammo ,like 168 Gr projectiles.

Wait for it....

 

 

 

 

 

 

 

 

 

 

 

Lube it up with Mobil One or Castrol GTX ! 

Dripping Wet, Running down your arm, Splashing in your face and dripping on the floor !!! This will break in your gun , 50 to 100 rounds . Run a patch through the barrel every 10 to 20 rounds.

The 147 gr bullets are not the best to be used for breaking in your gun. Also the buffer is a little heavy. Magazine could be the other issue, try the metal mag with the 168gr bullet then the Pmag with the 168gr bullet.

Good luck and tell us what happens. 

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Home build  147 FMJ. New gun   Magpul 20 round mag. First 10 rounds ran fine. 16" mid length DPMS upper and lower. Carbine buffer 11.25" spring and 3.80oz buffer. Ares Armour NIC bolt. 

  As had been said , run her wet . Sounds like its short stroking & as said , the BC is stripping the fresh round from the Mag & not the Bolt face. Test as said , with one round in the Mag to see if the BCG goes back far enough in recoil to lock back BCG on last round . The fact that she ran with the first ten rounds may mean not enough lubrication & the BCG is binding or slowing down on recoil . 

     Check your Gas Block to make sure it hasn't loosened up or moved .

     How far does your Gas Tube protrude into the Upper Receiver ? Photo's ?

     How many coils in the Buffer Spring ?

     Whats the length of the Buffer ?

     Has the Head Space been checked ?

  Rifle should function reliably with good 147 gr. Ball Ammo . I use M80 ball to test all 308AR's I have built .

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Okay,  I will not get time to shoot the gun for awhile. So I CLP the hell out of it. Just manually running the bolt by hand. If the bolt is locked back and I hit the bolt release it will chamber, pull the charging handle back the whole way and let it fly, it will jam every time.... It seems that when the bullet hits the feed ramp it shoots the bullet upwards to much and thats when the bolt will jam about in the middle of the case... I did try a Brownells Metal mag did not make a difference 

 

Edited by 05titanle
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05.....so do what the brothers have suggested for sure.....my 2cents....you proly have one or two things going on...we have to eliminate the short stroke gas problem first....but you just stated it boogers up on charging..  when you put in the mag release..did you screw the lever down till it almost hits the lower...do the mags rock or feel loose in the magwell? Can you get it to feed by holding the mag a certain way? So off the bolt catch it feeds......But...when you pull back and let fly it fails to feed? Heres what a stock dpms buffer looks like and spring..we gotta start from first base.. also...pull the charging handle back and let the mag catch hold the bolt.. ....then pull on the charging handle and measure to see how much further you can pull the bolt back off the bolt catch?       Wash

Oh...the inside length of the buffer tube is 7 inches for the spring and buffer pictured here ....is that the tube you have?...and when you installed the mag release did you take a punch or screwdriver and push the mag button down while spinning on the mag release down to the lower? Is your upper/lower fit nice and tight ?

 

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Edited by washguy
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05  you gotta do this....   pull the charging handle back and let the mag catch hold the bolt.. ....then pull on the charging handle and measure to see how much further you can pull the bolt back off the bolt catch?    

 

"Bolt lug is hitting the back of the case to push it forward..  " .. I dont understand what you mean?       ive never had a Dpms car buffer at 2.25...all of mine are 2.50   and you said off the bolt catch it feeds fine in your post...right?...pics would be nice    Wash

Edited by washguy
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Washguy,  I dont understand what you mean "  pull the charging handle back and let the mag catch hold the bolt."  do you mean the bolt catch?  My buffer is 2.50" not 2.25... I'm coming up with 28 coils.  When i pull the charge handle back and lock it with the bolt catch, I can pull the bolt back about 3/16" more...  When I said "Bolt lug is hitting the back of the case to push it forward. What i mean is the bolt is pushing the case forward and not the carrier..

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Im sorry sheesh I mean the bolt catch...duh....well..I just went and looked at 3 of my ar'308's...they all have a dpms car buffer /spring and they all pull back off the bolt catch a good 3/8 of an inch backwards to where it stops in the buttstock....so does it still feed off the release of the bolt catch,but not when you pull the charging handle back?...lets see some pics     Wash

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We need a pic of the bolt held open by the bolt catch with and without a mag...with a cartridge and without one. If you cant even get to the point of feeding when you pull back the charge handle...something is very strange....sounds like your mags are sitting too low in the lower...did you hold the mag in different positions while trying to charge? is the mag tight or loose?...take out your bcg and take it apart...look for shavings...under the extractor too...lets see the spring setup under the extractor...does the bolt/cam move nicely?  

and you said the first 10 rounds ran okay.......inspect your bcg for shavings and lube it up      Wash

Edited by washguy
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