problems with new AR pistol build

[blksniper2000]

Ok so i put together a AR pistol using a spikes lower, psa 10.5 cold hammer forged upper, psa lower parts kit, wmd nib bcg, and a phase 5 pistol buffer tube assembly kit.

So the first time firing it at the range i load a mag, fire it once and the bcg gets stuck while feeding the second round. the hammer does not reset and the round was not fully seated in the chamber. I was unable to pull the bcg back to clear it, I had to actually use my ar wrench to take off the buffer tube to release pressure from the spring, next separate the upper from the lower, then take a small hammer and tap the bcg forward a few millimeters to chamber the round, put it back together and fire it to clear the round.

I took it home and cleaned it then tried it on another day, I made it through maybe 4 or 5 rounds and the same thing happens again, I had to repeat the same steps to clear it.

Any thoughts or ideas?

 

[BradMacc82]

Gas or buffer/buffer spring issue, sounds like there's not enough gas-pressure to cycle reliably, or the buffer/buffer spring combo is too strong.

What type of ammo were you running??

 

[RW2111]

Yes agreed with above post, the weapon is most deffinetly short stroking I would look at your gas setup first, which buffer are you using

 

[wilcam47]

also is the bolt lubed well? It does sound like a gas problem though..

 

[Blu Falcon]

Gas or buffer/buffer spring issue, sounds like there's not enough gas-pressure to cycle reliably, or the buffer/buffer spring combo is too strong.

What type of ammo were you running??

This.

 

[04RWon]

Something doesnt sound right if he couldnt pull the charging handle/bcg back. Short stroking is one thing but getting stuck.

 

[jeffersm]

Buffer spring is my vote.

 

[BradMacc82]

It was likely stuck on top of the round it failed to strip from the mag...

 

[blksniper2000]

Gas or buffer/buffer spring issue, sounds like there's not enough gas-pressure to cycle reliably, or the buffer/buffer spring combo is too strong.

What type of ammo were you running??

I just went and checked my mags, I had both factory pmc 55grn and some 55grn reloads Ive used in my other ar's with no problems. I honestly can't remember which rounds were used in the pistol.

 

[blksniper2000]

Yes agreed with above post, the weapon is most deffinetly short stroking I would look at your gas setup first, which buffer are you using

I'm using the spring and buffer set that came with the phase 5 pistol buffer tube

Do you guys think i should try the lower with another one of my ar uppers? they are 16" though

 

[BradMacc82]

Try some NATO-spec loads and see if it short-strokes, PMC and most reload data is only loaded to .223 REM pressure, you might need that extra bit of pressure from mil-spec ammo to get things moving properly.

 

[04RWon]

It was likely stuck on top of the round it failed to strip from the mag...

Dropping the mag should have cleared that.

 

[04RWon]

I just went and checked my mags, I had both factory pmc 55grn and some 55grn reloads Ive used in my other ar's with no problems. I honestly can't remember which rounds were used in the pistol.

Ive broken all my rifles in with pmc bronze 55gr or pmc xtac 55 or 62 gr. Its good ammo.

The round wasnt partly stuck in the chamber was it?

 

[TyFromMD]

I had a problem with my bolt jamming on my 7.5" pistol when i fired it with no muzzle device. I had to separate the Upper and lower to get the bolt out. When I added a KX3, the bolt stopped jamming, but the casings failed to eject. I switched my buffer spring from the pistol spring my spikes pistol buffer tube kit came with to a carbine spring. Seems to work just fine now.

 

[jrumann59]

Ive broken all my rifles in with pmc bronze 55gr or pmc xtac 55 or 62 gr. Its good ammo.

The round wasnt partly stuck in the chamber was it?

My spikes hates PMC, I have used mix mags of PMC and federal, I have gone PMC and federal every other one and my AR finds the PMC and short strokes. It is the only ammo to date this happens on. 2000 rounds through without an issue since I stopped using PMC

 

[04RWon]

My spikes hates PMC, I have used mix mags of PMC and federal, I have gone PMC and federal every other one and my AR finds the PMC and short strokes. It is the only ammo to date this happens on. 2000 rounds through without an issue since I stopped using PMC

Very very weird....even my old spikes ate the stuff. No brass has ever given me a problem. Using stt2 buffer? I assume spikes m16 carrier?

I ask bc oddly my gf's rifle, bcm 16" middy, did not like tula when she ran an ar15 carrier. Now with the m16, it doesnt have an issue. Shes always run a stt2 buffer.

 

[BradMacc82]

Dropping the mag should have cleared that.

In theory, but the round could've been half out of the mag and half into the barrel extension, that could've locked things up to where he couldn't drop the mag easily(?).

OP didn't clarify that, so we could go on with theories, but that doesn't get his issue resolved.

 

[Ruzo]

With out reading all the posts but the first couple. I have to agree with earlier post, sounds like a pressure issue. A common cause is a problem called "short stroking" when there isn't enough pressure to allow the bolt to go back far enough to pick up the next round, after firing and ejecting the first. Check your gas block for defects.