Dragging this thread back into the light since it's only a couple months old and it intrigued me when it was first active.
After reading this thread I picked up a package of "
Super Bang Ring Caps" from the local grocer (link goes to Amazon). I finally tried them last night on my stainless Pietta 1858 Remington.
Out of 39 shots with the ring caps I had 2 or 3 misfires. The first time I had a misfire I tried recapping with another ring cap but it still wouldn't fire. I then put a CCI cap on the nipple and the gun fired immediately. I think the flash channel was at least partially clogged and the toy caps didn't have enough oomph to punch through.
The impression I get based on last night's trial is that these toy caps
are viable substitute for commercially produced percussion caps, at least for use in percussion revolvers or rifles like my Hopkins & Allen underhammer, in which the nipple's flash channel goes right into the powder.
However, the toy caps aren't as hot as CCI or Remington percussion caps. Whether they'll work in a sidelock rifle like my Cabela's Hawken, or with BP substitutes like Pyrodex or Triple 7 are things I want to try.
The plastic caps stayed mostly intact on firing though some got pretty shredded. I was shooting 30 grains of 3Fg Goex under a wad and a.454 ball. I used the reamer on my SAK to pry the spent caps off the nipples.
They are corrosive but since I clean with water based solutions I don't worry about it.
But for just a couple bucks for 160 ring caps, they make sense for informal paper punching.