Dugaboy1, that's interesting. I'm thinking now that body weight may also play a factor - at least at how much of a jolt and movement occurs. I weigh about 77kg (170lbs?) which is reasonablly light. The recoil movement is more with us lighter guys so maybe this can cause the sear/trigger to jolt and fire on the front trigger system? Of course this assumes that you weigh more than me but I think I'm not too far wrong (am I?).

I went to our BGR Nationals last year and most guy were 200lbs or more, so I reckon most of the big bore shooters are big guys - right/wrong?

I even have to lean into a CZ550 (heavy rifle) 375H&H otherwise I have to take a step back when it fires. While I do hold the 500 firmly (hasn't flown out of my hands and doesn't hurt to fire), I suspect my body mass may be too light to slow the recoil and limit the movement it causes.