Im just getting going with this new URG that I put together but Im really digging it so far.

Sionics offers 3 different gas ports in the 11.5 inch barrel. Standard, Reduced, Extreme Reduced.

The barrel I chose is the extreme reduced gas port for smooth shooting with a suppressor. It's not recommended to use this barrel unsuppressed due to possible reliability issues.

Ive found that this upper shoots really sweet in 2 different configurations:
1. Suppressor/standard weight carrier/H2 weight buffer
OR
2. Muzzle brake/low mass carrier/carbine weight buffer

I like having a non-adjustable gas block and now I just regulate the gun through mass (carrier/buffer) as opposed to gas.

Quick overview with some test firing in both "modes":