A friend has two, both are Browning A bolts. The 223 is fed the inexpensive ammo cans of 223s you find at gunshows. Some twisting of the BOSS and the ammo shoots 1/2" or so. The 300 WSM never required much tuning to get it to shoot. It shoots 125 Nos bt AND the 230 Berger hybrid equally well. (talk about extremes)
I found the comments on it being loud funny. Those holes in the BOSS make it a MUZZLE BRAKE! All over this site there are many that use a brake yet I don't hear how loud those are. Laughing......