Ar15 stove bolts second or third shot

[nekshot]

It is a aero lower with rifle stock. It seems jam 2 or 3 shot. Never got deeper in the mag. I built a few of these that function flawless. I am wondering about the spring in rifle tube? It would appear to be short stroking. But, what do I know?!

[czgunner]

Put a single 5.56 pressure cartridge in a known good magazine and fire. Does it lock back? If not, you have a gassing issue.

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[Sig556r]

you shooting factory 223?
pistol, carbine, mid or rifle gas system?
bolt holds open on empty mag?

[nekshot]

It’s a rifle with original type stock. Remington green tip ammo. The cartridge ends up pointed up into the breech but the bolt is kinda on top of it.

[country gent]

Do you have the correct buffer in it? Is the gas port and gas system aligned correctly" is the gas tube entering the key smoothly and not binding?

[BK7saum]

Does it occur with all magazines? Rule out magazine first.

Verify correct parts.
Swap to a known good lower.
If still having problems, then diagnose upper vs lower, gas port alignment/gas block, gas key on bcg, gas rings on bolt, etc.

Also, Too little gas and too much gas can have common symptoms. Both can appear to be short stroking where too much gas is overrunning magazine spring.

Several things need to be checked and verified to eliminate variables.

[Texas by God]

It’s a rifle with original type stock. Remington green tip ammo. The cartridge ends up pointed up into the breech but the bolt is kinda on top of it.

That usually means that the loads are underpowered. Like said above if it won’t lock open on an empty magazine after firing, it’s wanting more gas.


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[1Hawkeye]

Another thig to check is the bolt carrier key. Make sure its screwed tight to the carrier if its loose it can drag and slow down and prevent proper function.

[Gtek]

With so many parts that have been slammed out over the past decade or so? Pinned FS assembly? gas block with set screws floating guard? Some barrels were machined to have hand guard ferrule behind block. Orifice sizes were all over the place and stack up of this and that can reduce 30-40 percent not counting if block is misaligned. Loose key, cheap bolt, rings bad or lined up. One of my peeves is that gas tube key interaction, put in tube, pound in pin, good to go. NO, NO, not even close! Maybe one out of ten will be close. Pull bolt assy from BCG, have upper horizontal and right side up. Put your pinky in the back of BCG and push into position and feel capture of tube into key, anything past a bump it needs some thumbing/tube tweaking out front to get to right in mine.

[nekshot]

Ok, thanks for all input. As soon as it warms up a bit maybe by Tuesday I will venture out to shop and have a look at this ar again. Too cold and I am 5 weeks out for a knee replacement so things are in low gear for getting about!

[John Taylor]

sounds like a mag problem to me. The term stove pipe was usually used on lever guns where the cartridge was standing strait up instead of going into the chamber. The 1892 Winchester had this problem when the feed rails were not right. Feed rails on an AR are the mag.

[mulespurs]

Try oiling it

[popper]

Bolt over-ride. If not under gassed, mag problem likely. Either bolt is moving too fast or bolt lug doesn't pick up case head. Can be mag spring (weak) or lips hold base too low in mag. Recoil spring may be too strong or buffer too heavy. Start with mag first.