308 Issues

[swampfoxx]

My son assembled a 308 using the DPMS standard parts from different manufacturers (LR-308). It has failure to feed after the first round. It has an 18" barrel, mid-length gas, adjustable gas block, rifle buffer tube, 5.4oz rifle buffer and rifle length spring. When charging with the charging handle, it fires fine, cartridge ejects at about 2:00-3:00, and it feeds the next round, but the trigger won't function and it feels like it is not going into battery. Forward assist doesn't do anything as the BCG does not have the ridges on it. Pulling back the charging handle ejects the bullet and feeds another one, and the cycle repeats. We tried adjusting the gas and tried a 3.5oz carbine buffer, but it didn't change. When loading only one round, the bolt locks back on an empty mag, so I'm sure it has enough gas. I am thinking it needs a stronger spring?

 

[Bigchillin83]

Either that or it’s a tight chamber, shooting quality brass ammo or steel case/ or cheaper brass mil spec ammo?

 

[Bigchillin83]

Kinda weird the trigger is reseting and locking bolt on empty mag… sounds kinda like a tight chamber issue or maybe off spec chamber.. if you drop a live round in or charge a live round in chamber, does it drop out freely or come out easily with charging handle?

 

[swampfoxx]

I will check on both of the above questions. He was supposed to come down last weekend but took my granddaughter to a slumber party instead.

 

[jdindadell]

Check to make sure that the roll pin that holds the extractor in place on the bolt is properly seated below flush. It can interact negatively with the barrerl extension and cause the bolt to not shut fully. I have seen this twice. both times on a 308 ar.

 

[Frisco]

Not sure what magazines he's using but I've had similar issues with both of my AR 308's. I switched from Pmag's to Lancer, now they run flawlessly .

 

[hotbiggun]

Ditch the adjustable gas block.

Contack Slash at https://heavybuffers.com/ the guy is very knowlegable

 

[new_bayu_shooter]

Try the easiest thing first, a different brand magazine. I purchased a AR-10 that would fail to feed and jam up after the first round. Switched to PMAGS and it worked flawless.