Slow hand
It's actually this one
https://silencerco.com/asr-single-port-muzzle-brake.html
Yes the barrel was cut shorter than 16" and the muzzle brake permanently attached.
I figured it was cheaper to get blast shield than going thru a gunsmith.
Thanks guys!
Complete thread:
- ASR blast shield - 
Frank S, 
2020-01-23, 16:43 
- get a micrometer, caliper or good ruler and count - bj, 2020-01-23, 20:29
 - Thread gage - Brien, 2020-01-23, 20:59
 - ASR blast shield - 
Slow Hand, 
2020-01-24, 04:44
- Slow hand - 
Frank S, 
2020-01-24, 05:00
- Slow hand - Slow Hand, 2020-01-24, 05:54
 
 
 - Slow hand - 
Frank S, 
2020-01-24, 05:00
 - ASR blast shield - 
uncowboy, 
2020-01-25, 06:54
- ASR blast shield - Frank S, 2020-01-25, 16:56
 - Uncowboy - 
Frank S, 
2020-01-28, 10:18
- Uncowboy - Slow Hand, 2020-01-30, 17:24
 - The man is a super-genius. NT - guest, 2020-01-30, 21:28