300 blk build cycling issues FTF

[Plinker66]

I believe my BA blackout chamber was really tight, too, until I ran a few hundred rounds through it.

 

[C'mon man!]

I believe the BA feed ramps aren't opened up for the larger diameter bullet, they're the same as the 5.56 feed ramps. Which could change the angle in which the round drives up the feed ramp, it could potentially be aiming too high and driving above the chamber. This matters more with round nose/flat tip bullet profiles. There are youtube videos of people taking a dremel to open them up. This may or may not be your issue.

 

[Quacker]

Does it lock back on an empty mag? That would be my first check.

My 300 blk with BA 8" barrel and H2 Buffer Aero Precision build hasn't had an issue yet with the Gen 3 Pmags, but I've also only been shooting subsonic rounds, haven't tried supers yet.

Yes it does with both g2 pmags and the mission first

 

[Quacker]

I believe my BA blackout chamber was really tight, too, until I ran a few hundred rounds through it.

I figured there would be a break in period with this. Just didn’t think it would be this hard to break in. Thinking I’ll lube the crap outta it and run pmags next

 

[sweathogger273]

What? Why?

Bcuz i gotta 223 that had a standard pin and it will dent the primer so i swapped pins not a issue since

 

[fast306stang]

any updates Quacker ?

 

[Quacker]

any updates Quacker ?

Haven’t had the chance to make it to the range yet. Hopefully this weekend or the next at the latest

 

[Quacker]

Ok. After lubing the crap outta it and using aluminum Okay industries mil spec magazines, I am still seeing ftf/fte and those 2 gouges on the case. After hand cycling a few rounds and shooting some slow mo footage I am convinced it is the feed ramps on the barrel that is gouging the bottom of the shoulder on the brass. That explains why the rounds still chamber but are getting deformed so much not to go into battery.

But why is this happening? Mags sitting too low in the receiver? seems like the rounds are being forced up at too high of an angle.

I may call aero precision / ballistic advantage to see what they have to say. I believe they are essentially the same company now.

Thoughts? Comments?

 

[Deleted member 79987]

Ok. After lubing the crap outta it and using aluminum Okay industries mil spec magazines, I am still seeing ftf/fte and those 2 gouges on the case. After hand cycling a few rounds and shooting some slow mo footage I am convinced it is the feed ramps on the barrel that is gouging the bottom of the shoulder on the brass. That explains why the rounds still chamber but are getting deformed so much not to go into battery.

But why is this happening? Mags sitting too low in the receiver? seems like the rounds are being forced up at too high of an angle.

I may call aero precision / ballistic advantage to see what they have to say. I believe they are essentially the same company now.

Thoughts? Comments?

I’d take it to a local gunsmith who specializes in AR’s, but that’s just me.

 

[Quacker]

Called BA. they were really helpful. They said they have never seen anything like this. He asked how they were ejecting and I told him it was slinging the brass about 10 feet to my 0400 position. He said it sounds like it’s not a gas issue. Bolt be traveling too fast so we might want to slow it down with a heavier buffer or subsonic loads just to see. He recommended going through the process of elimination and try a different BCG, mags, buffer, and possibly remove the scope just to see how she responds. Sounds like I’ll need some more ammo for Black Friday!

Now accepting donations