First time post here. Got my handi in 223 bull barrel about 2 weeks ago. I just could not get it to shoot very good groups at 100 yards. Then I found this place (very cool !!) I o ringed the lug and BAM! I now can put 3 shots in a postage stamp at 100 yards with 55 grain reloads and a ragged hole with Winchester white box. Thanks to everyone for the great info. Be safe