ar15 is short stroking?

[fayettefatts]

Bolt carrier dragging on hammer?

 

[cjmac]

Cycles by hand normally. It is a ar15 spring. BCG dragging on hammer is something i never really thought about . I guess if its to much it could be a problem

 

[akajun]

Put the upper on another lower that you know works . If it cycles reliably, look in the lower .
Things to look for in the lower, improper buffer , spring, or buttstock screw. Also , but somewhat less common, is certain match triggers cause more hammer drag, bushmaster 2 stage triggers if adjusted improperly will do this.
In the upper, look for a bent or misaligned gas tube in the upper , causing drag on the key. Worn gas rings. To check for this push the bolt in the carrier, then pick the assembly up by the lugs , the bolt should stay pushed in. Lastly, check the gas port size. On a 20" barrel in 223, it should be .089 to .096. Buy some wire size reamers from enco if you want to open it up .

 

[Road_Clam]

I had two different "short stroke" type issues with my Bushmaster, the first was I was handloading too fast of a powder (4198). The second was a broken rubber bump stop at the end of the buffer piston.

 

[itchyTF]

I had a 20 Practical barrel from WOA that short stroked. They opened up the port and problem went away.

 

[mac86951]

Put the upper on another lower that you know works . If it cycles reliably, look in the lower .
Things to look for in the lower, improper buffer , spring, or buttstock screw. Also , but somewhat less common, is certain match triggers cause more hammer drag, bushmaster 2 stage triggers if adjusted improperly will do this.
In the upper, look for a bent or misaligned gas tube in the upper , causing drag on the key. Worn gas rings. To check for this push the bolt in the carrier, then pick the assembly up by the lugs , the bolt should stay pushed in. Lastly, check the gas port size. On a 20" barrel in 223, it should be .089 to .096. Buy some wire size reamers from enco if you want to open it up .

+1 to those suggestions, if cycles by hand normally and doesn't function on another lower, then for sure you're not getting enough gas. Check gas port alignment first (look for carbon buildup under gas block), then Check the key on the bolt carrier is staked and sealed, followed by a gauge of the barrel port size.

-Mac

 

[Big Bore]

Do you have a rifle stock or carbine stock and do you have the correct spring and buffer for that stock?