got a SBEII as well had the same problem shooting B, thru my kicks choke, i caught it fast when i noticed the threads sticking abit. had the full choke too, read the fine print, lol observed not to be used with large shot, using a modified now for b and bb. luckily only the threading on the fullchoke itself appears to be damaged as the modified screws in well. guess i'll use the kicks full for number one shot and smaller.