I've had this problem the last 4 or 5 times I've gone to the range. I went again today and had the same problem. Basically I'm perfectly fine until I've shot off about 25 rounds or so. At that point a muscle in my forearm will start twitching or spasming and it will cause my hand (and gun) to shake really bad from left-to-right. It will go away the moment I let go of the gun or if I point the gun down low. But as soon as I hold the gun up to shoot the target, it starts in again. You'd think I had parkinson's disease from the way it looks. So I'll typically switch to shooting with my left hand, and everything is fine. It is only my right arm that is doing this. Funny thing is, I can't even reproduce the problem outside of the gun range. I can hold my gun at home and point it in the exact same manner, and it doesn't seem to happen. I asked the range master today if he had heard of such a thing and he had not. So I'm kind of stumped. I suspect it is a nerve problem since it only happens when holding my arm in a specific way.
From a self-defense perspective it doesn't seem to be much of an issue as it doesn't start until I've fired off at least 25 rounds. But it sure does take the joy out of going to the range. As you can imagine, my accuracy drops dramatically after that problem kicks in. I suppose in time I may learn to shoot as well with my left hand, but I sure can't right now.
Anyone ever experienced this or heard of it before?