you mean fffffttt ...............................bang ?
nothing noticeable - was only firing blank powder charges to test ---pull trigger - gun went bang
I pulled the nipple on a couple of the no fire events to check things and the powder charge was right there visible at the end of the nipple -- those toy caps just didnt have what it takes I think - I got plenty FFFF priming and the little brass dispenser flask. only takes a few seconds to top the nipple up before putting the cap on and every one of those went off .
I will modify a nipple for the plastic caps they a little smaller fit and occasional one splits - what I have came in pack of 144 and I think was two bucks
I bought a bagful of cheap roll caps but they so weak most of em wouldnt even fire ditched those - havent seen the good red ones for years.