re: Official AR-15 thread

Finally got my 300blk tuned in yesterday. Had to drill the gas port diameter out all the way to an 1/8" and switched from an Aero adj. gas block to a standard low profile gas block. I think part of my problem was I had alignment issues.

- S&B 220gr began to cycle (did not cycle before current setup) but did not stay open on last round.
- Winchester WB 200gr cycled 100% and stayed open on last round.
- Reminton GB 220gr cycled 100% and stayed open on last round.

Had to learn about ammo types and chamber pressure vs gas port pressure from this video:

Cycling Subsonic 300BLK Ammo

Well, now that the gun fully cycles, this gun kicks like a mule and the gas is horrendous. Ejection pattern is perfect at the 3/4 o'clock position. Any adjustment there I feel like it's going to put me back to where I started. Which has lead me to this question:

Have any of you bought this KAK K-Spec BCG with "Down Vents"?

What it does is instead of ejecting the gas out of the 2 holes in the side of the carrier, it diverts it with 4 holes in the bottom of the carrier into your magazine and trigger housing.

KAK swears up and down that this isn't an issue and apparently, they have sold hundreds, or maybe even thousands, of these in addition to 1000s of rounds test fired. It's a $200 BCG. You can get the carrier for only $110 though.

For those of you that have bought it, was it worth it?

https://kakindustry.com/ar-15-parts/bolt-carrier-group