FTE 300 BKT

[kindofsudden]

Hey all. Almost done with my 300 BKT pistol build (7.5" barrel DI). Gibbz side-charging upper.

It fires great, but fails to eject. I have the problem suppressed AND unsuppressed. I can manually cycle the round just fine, it just doesn't cycle itself when I fire. I've tried different rounds and different mags. I was using a normal buffer and spring, but also tried H2 buffer and shorter/softer spring with no change in result. I have the same BCG, stock, and buffer in a 5.56 and everything works great.

Thoughts? Thanks ahead of time.

 

[Ernest 5.56]

What's your gas system length?

Does the gas block fit tight on the barrel is it aligned properly?

Have you tried normal buffer paired with the softer spring?

 

[hafejd30]

When you say doesn’t eject is it able to lock back on an empty mag? Or is it short stroking?

Also subs or supers?

 

[kindofsudden]

What's your gas system length?

Does the gas block fit tight on the barrel is it aligned properly?

Have you tried normal buffer paired with the softer spring?

Gas tube and block appears to be about 5". Gas block fits tightly and appears aligned. I've tried all combinations of buffer and spring mentioned.

 

[kindofsudden]

When you say doesn’t eject is it able to lock back on an empty mag? Or is it short stroking?

Also subs or supers?

I haven't check to see if it locks back on an empty mag. I don't think the bolt is coming back at all. I've tried both subs and supers.

 

[SuperBoot]

300 BKT

Ah yes I am also a fan of 300 Bucket

 

[msgriff]

If you have tested the same exact BCG that is in the 300BO in another firearm, and it functioned properly, you should be able to rule that out. I would verify gas block alignment, "appears aligned" is somewhat vague.

 

[hafejd30]

A cheap borescope would tell you if he gas block is aligned. If your bolt is hardly coming back it’s likely that. Turning off the gas would do what you’re experiencing

 

[kindofsudden]

UPDATE: Looks like I have an "i d 10 t" error. Short story: I swapped out another upper for this one, and forgot that this upper has an adjustable gas block. It's my first AGB, and I learned that this manufacturer ships them with the gas port CLOSED. So yeah, I opened it up and it's running perfectly now. Thanks for the helpful hints!

 

[DHDeal]

I can say without a shadow of a doubt that I have never done that! I might have (allegedly) put a rifle length gas tube upside down once but I have no memory of the event....