I have a sentry 7 AGB for my Faxon 12" group buy barrel underneath a Mega Arms 12" MKM with a Sandman S about an inch under the handguard. The GB fits under the handguard without any issues and the sandman seems to fit tight without any issues with accuracy. I was around MOA and under on about 100 rounds fired during a course of the day. Many were cloverleafs at 100 yards.
I have a bootleg adjust BC in my 18" 6.5 JP enterprise barrel I just bought and the price is reasonable at 139.99 a few weeks ago. I changed my rail to a Geiselle 15" because I didn't like the previous rail on it and ran into issues with the Sentry 7 AGB touching the Geissele rail. I switched to the Geissele GB that came with the rail and that gas block was just shy of hitting the rail too. I had to file the metal block that comprises of the large set pin hole down on the Geissele GB so it wouldn't interfere with the rail. When I switch rails, I bedded the barrel in the receiver with blue 243 loctite to see if it would impact my groups. It was shooting around MOA with black prior to be touching it but I think it should be better. The barrel extension was pretty loose in the upper receiver without the loctite.
ETA: both of my JP and Faxon barrels hates wolf. I'm at 6 to 7 inches depending on how many I shoot in a group. Funny thing was the first three Wolf rounds that I shot cloverleaf at 100 yards with the Faxon barrel. It was a hot messy after finishing the rest of the 7 shots though. After running another 50 rounds of Wolf, I gave up and will not shoot past 25 yards with them and probably will not buy any more since it is terrible at 100 yards.
I have a bootleg adjust BC in my 18" 6.5 JP enterprise barrel I just bought and the price is reasonable at 139.99 a few weeks ago. I changed my rail to a Geiselle 15" because I didn't like the previous rail on it and ran into issues with the Sentry 7 AGB touching the Geissele rail. I switched to the Geissele GB that came with the rail and that gas block was just shy of hitting the rail too. I had to file the metal block that comprises of the large set pin hole down on the Geissele GB so it wouldn't interfere with the rail. When I switch rails, I bedded the barrel in the receiver with blue 243 loctite to see if it would impact my groups. It was shooting around MOA with black prior to be touching it but I think it should be better. The barrel extension was pretty loose in the upper receiver without the loctite.
ETA: both of my JP and Faxon barrels hates wolf. I'm at 6 to 7 inches depending on how many I shoot in a group. Funny thing was the first three Wolf rounds that I shot cloverleaf at 100 yards with the Faxon barrel. It was a hot messy after finishing the rest of the 7 shots though. After running another 50 rounds of Wolf, I gave up and will not shoot past 25 yards with them and probably will not buy any more since it is terrible at 100 yards.