I have a Colt M1861 (from CBAC) that takes #11's, which is fine with me, but I've been unable to get CBAC to answer me about getting more if these wear out, break, whatever. It would really be nice if he could make these out of the alloy that used to be called "Ampco"; the stuff is extremely heat-conductive, so the heat never gets to them long enough to cause erosion. The Ampco company went out of business up here in Milwaukee some years ago, and I don't know who holds the patents, if anyone. The stuff is a Beryllium alloy, and it is my understanding that Beryllium dust is extremely hazardous to work around; that may be why no one else has taken up the manufacture of the alloy.