Maybe way back when they wrote the owner's manual that's what fit the nipples of that time. Remington#10 are more gorgiving and expand a bit as they are seated. CCI #10 are way smaller and way harder to seat on a tight nipple.
Hold on. I've had guns that wont fire #10's unless seated perfectly. I have had 2 uberti 51 navys that one would fire #10's and the other wouldn't. The answer that I got from an other source was to buy treso nipples that fit # 11's. They fit 11's perfectly. They do! They do not fall off and you don't have to pinch them.
My Ruger Old Army works fine with Remington 11 but my Walkers need CCI 10 or the caps want to fall off. Might not be easy to find but if you do business at that store they can order you some.
I've never had a misfire out of the factory nipples that come on the Piettas- maybe it's my loading and cleaning style...but they allow the caps split and turn them into shrapnel which either burns my hand, falls into the action or just reeks havoc unless I do the point to the percussion revolver dance.
That's why I changed nipples to Tresos- much smaller flash hole and better fit.
The problem with the Tresos is the price.
I've never had a misfire out of the factory nipples that come on the Piettas- ..but they allow the caps split and turn them into shrapnel which either burns my hand, falls into the action . . .
Exactly. I even found two flattened caps down in the frame of my 1860 last night when I took it apart for cleaning. But, I am like Keybear and have a whole bunch of Remington #11s and they are gonna get shot! (Then, I'll fix the issue)
Keep the nipples and re-size the caps. Caps are easily and symmetrically re-sized using a small socket from a ¼'' ratchet set. Either a 5/32” or 4mm size will work.
Simply place cap on hard flat surface open side up and apply downward force with the socket. A gentle tap may be required. If the re-sized cap resists being removed from the socket gently grab it with pliers and rock it back and forth.
I modified my socket slightly with a pointed stone on a Dremel tool to provide a forcing cone of sorts.