Sticking AR bolt/extractor Oring the cause

[JD4440]

So I finally got a chance to shoot my dissipator build this afternoon and it was a single shot for the first 20rds. Bolt didn’t even attempt to come out of battery. Bolt cycled fine by hand without a round. Chamber a round and it was sticking/hard to pull the charging handle back to eject the round. Long story short, I double checked everything gas related, was running out of ideas and then read something about the extractor o ring could cause a bind and bite brass off the cases. Removed oring and shot 5 consecutive rounds without fail. Anyone else ever had this happen? It’s a hodgepodge of parts but all new except A2 upper. BCG is a psa NiB. Mid gas system and rifle stock/buffer.

 

[Dirty J]

Are you sure you don't have a headspace issue?

 

[JD4440]

Are you sure you don't have a headspace issue?


Possible, bolt is closing fine on brass 5.56, just sticks trying to unlock the lugs. After I removed the oring it cycled fine and ejected fine, only fired 5 rounds b/c I was out of time

 

[Dirty J]

That could be indicative of the bullet engaging the rifling and getting stuck.

Any marks on those bullets when you clear the gun?

 

[JD4440]

That could be indicative of the bullet engaging the rifling and getting stuck.

Any marks on those bullets when you clear the gun?

Just hand cycled several and no land marks on bullets

 

[JD4440]

Update for anyone that finds this thread in the future. The charging handle was slightly sticking in the upper as well. Swapped it with another ar I have and rifle functioned flawlessly. After break in I may put the extractor o ring back in and test just to see but it had no problems slinging brass with just the spring today.