Referenced product: UAM400-16B-E-KIT
This is not an adjustable gas block.

Referenced product: RM400-16B-TRD
The M400 Tread has a 1 in 8" twist and the gas system is mid-length.

Referenced product: UAM400-16B-E-KIT-SOR52001
We package the Romeo5 with the upper. The upper comes from Sig. The barrel is nitride coated. This has a carbine length gas system. The upper weighs 3lb 5oz and has a 1 in 7" twist. The gas block is Sig'...

Referenced product: UAM400-16B-E-KIT-SOR52001
Sig used to offer this but discontinued it. We have sold about 500 and have not heard complaints on the rail.

Referenced product: LWR-ASSY-M400-516-TELE
Response Date: Mar 9, 2019
As far as we know, the LWR-ASSY-M400-516-TELE should be compatible with the PWS uppers.

Referenced product: UAM400-300B-16B-ECP-FDE
Response Date: May 16, 2019
Yes. This is compatible with a M400 lower.