Seems this is a common problem with the Handi's in general. Searched ad-nauseum - lots of similar posts but no solutions! If Fred had a solution posted, it disappeared!
Just got a 357 barrel for my sb1 frame. Works fine till you load up anything approaching a full load, then the primer flows back into the firing pin hole enough you have to pop it across your knee to break the frame open. These are, BTW full house per sec but not max loads, even in sets of six, these rounds extract easily from both my Colt and DW. As an aside I noted the same thing on my SB2 even working up loads for my 223 barrel, anywhere close to max and it'll start hanging on the pin hole a little as well, luckily just not as bad as the SB1. I'm kinda wondering the sanity of trying to get the 357 max to work out on the SB1 frame after I get it reamed. Bushing the frame and a smaller better fitted firing pin would surely work but that's a bit past my equipment skills here. Has anyone tried as in when I try the MAX using small rifle primers? I'd think perhaps it'll lessen the problem if nothing else.