Jack Spade turned me onto these and they work fine in my guns, with over 5000 used both brass finish and nickle finish. My pistols and Marlin (both 38's) have lighter not ultra light springs, I also shoot them in my 9mm competition guns without issue. I will say that for bigger matches I use Federals. I have used a variety of European primers Tula, Fiocchi, Wolf and they are all a gnats rear end bigger than American made primers and do not seat with the ease of their American counterparts. If you are used to the ease of priming with American primers they will not be for you.