The question was about Black MZ. I use only Goex in my flintlock rifles, but I use Black MZ. It does not build up in the barrel, and comparing it to some out-dated sub is not fair. If you follow the manufacturers recommendation, and pack it tight, it is very accurate. I've used it out of ROA, 32 cal. Cherokee, and 50 cal. TC Hawken. I got good groups and it did not build up in barrel, it was easy to clean. It's the least expensive of all the subs, at Shooter's Discount, at less than $23. a can. Takes less per shot, which stretches it farther. And, I like supporting the local folks. Alliant not to far from me. I would recommend it for cap lock guns only. One reason I think it works good in small cal. barrels, is because there is no build up. I shoot the little 32, 15-20 times, without cleaning between shots. The last shot went down as easy as the first. I have not chronograph, so I guess I'm still experimenting at this point.