I use CCI #10s on my Uberti 51 Navy with no problem. I bought some CCI #11s for my Hawken and have had nothing but problems. They will hardly ever fire the first time. Even being very careful and pushing them down very slowly with the hammer, with the muzzle down range, trying to make sure they are seated on the nipple, they still will not fire. I've come to the conclusion they do not fit the nipple (didn't take to long to figure that one out) so I went back to German RWS. I've never had a problem with them and they are what I shot until I couldn't find them anymore. Luckily I finally found some and bought ever tin of them they had. I can't find Remington's around here, but when I run out of RWS and if I can't find more, I'll try the Remingtons. And yes, I did change nipples with the CCIs, still had problems even with a brand new nipple.