My cz has eaten two sparcs. One ran fine on a .223 for awhile, put it on my CZ when my first sparc crapped out. 500 or so rounds on my CZ and its doing funny stuff, like turning on when closing the bolt, or off, or not turning off ect. Thats with new batteries, cap on tight. I have one I got cheap off the EE (before the second one crapped the bed) and its on my M305, hasnt been fired yet. Be interesting to see how it holds up.