Mine do not. I charge the cap with a very small amount of black and then insert the roll cap punch out disk with the black button facing the powder. The discharge of the main charge pushes everything out of the nipple. I fired about 20 shots this week and the only failure to fire was due to a dry ball.
Can I ask why any residue left by any cap is an issue or difference?
They ALL leave residue.
That's why full cleaning IS always an issue when using bp guns.(?)
What's the difference when home making with "roll caps" or "prime all"?
Ya still gotta take'm apart and clean'm don't ya?
I was testing a gun I modified using different caps to see if they fired on the first strike.
I included home made caps in my testing.
I made a batch of prime all caps using a single roll cap to help hold in the powder so I could not tell the difference between caps that were made only with roll caps and those made with prime all. I had made them a long time ago and couldn’t remember which were which. The homemade caps left a red residue. Having asked my question here & elsewhere, a friend told me the prime all caps, not roll caps, left the red residue. They worked as well as any of the brands & sizes I tried with the gun.
I have the tool that’s called an 11 , It fits both pretty good especially because it often uses aluminum soda cans which is bendable …I see they do now offer a 10 but this is the first I’ve seen it.
The 11 works on Slixshot, Treso , stock Uberti & Ped shotgun ..