I read somewhere on this forum about using a small o-ring to surround the firing pin and keep the falling hammer from hitting it during dry fire practice, instead of using snap caps. I found some small o-rings in my catch-all bin and placed one around the firing pin. The o-ring is just large enough that friction holds it in place. You just have to remember to remove it after practice. It works. They are cheaper than snap caps and you can find them at most hardware stores. They come in a multipack for less than a buck so if you lose one, or in my case forget where I put it, you have plenty of spares. To whoever suggested the idea, thanks.