Like most of these arms, you'll have to experiment a bit, or possibly change out the nipple in order to use what caps are most readily available locally. Experimenting was a lot easier when caps were $1.25 a tin, of course......
The thing to remember is that cap sizes are really just a rough guide; in terms of Remington vs. CCI vs. Dynamit Nobel, they just aren't made to one single standard. #11 vs. #10 just means that a given manufacturer makes two sizes of caps, one larger than the other.
Find one that works on your rifle, and find something else to worry about.