I shoot BB, my first extended choke tube was a full choke, seemed ok, but pattern was not even. i then read it was a bad idea for a full, with BB steel, so i put an extended Modified, and used that for two years no problems, but pattern was still not really even. i recently just experimented and after reading an improved or implied choke was the way to go with BB steel, to get a tight group i did this, i put on an improved.........only used it on my last day for this season. holy smokes, guess it pays to follow instructions, the pattern is actually tighter than the full and modified i used, and the shot is very even in the spread, and i hit most what i aimed at which is a new thing for me. can't wait until next year.