I've shot very light cast loads for decades without problems and am inclined to attribute the blowups with very fast powders to double and triple charges. That 180 WC sounds good, but RBs in the .430 to .435 range would be even better. I found a Lyman .433 mould w/handles in a junk store. Haven't done as much with it as I should, but it shoots pretty good to 25 yards from a carbine.
If you can't readily find anything in that range, you can just run .440 or .445 through your sizer. For your purposes, a box of 100 would liklely be all you would ever need.