Adj gas block adventures (1168)

[1168]

I shot some today with an adjustable gas block, and compared settings unsuppressed and suppressed with different springs and doodads.

I used an upper assembled with an A1 flash suppressor used to mount Griffin cans (MSDk, 30SDk,) a BRT 16” pencil barrel with longer-than-mid gas, and a Sentry 6 Ti click adjustable gas block. I used a FCD/Sionics BCG that has been used enough to trust. In two configurations, I used a LMT Enhanced BCG, recently rebuilt (springs, rings)

I got together 3 lowers; one with a Carbine RE, one with an A5, and one with a Rifle RE and A1 stock.

The following buffer weights were used:
Carbine buffer: 5.5oz
A5 buffer: 5.4oz
Rifle buffer:5.7oz
The rifle and carbine buffer were solid for consistency. The A5 was as it comes out of the box, with bias spring.

All numbers are minimum number of clicks open required to consistently achieve LRBHO with a Gen 3 PMag, and the rifle held firmly to my shoulder. This gas block has 3 clicks per turn, and a click is roughly 0.01” of adjustment screw travel. The first click is numbered 1, and so forth. Temp was ~60 degrees F.

Ammo used for testing was Federal XM855. I fired fouling shots with .223 handloads. I wiped off the bolt and carrier frequently to maintain consistency. No oil was used, and the gun started out dry.