You may have mis-understood what I meant or I might not have put it across correctly for that matter. I haven't really had any problems with that '60 and the caps fitting but it did teach me to modify my capping technique a bit.
It's hard to explain without a visual but when I cap using the snail capper I simply push down with my thumb on the capper right behind the cap and give her a little "wiggle" before I pull the capper off. I do this out of habit now on all my guns but on that particular one if I'm lax they won't be seated completely, then I grab the popsicle stick and lean on the cap a little more. Having one of those little buggers rub on the recoil shield as the cylinder rotates another chamber into battery would give me the willy's I'm afraid. It isn't a big enough problem to warrant buying Treso or Stainless nipples for it.