The guy who had the safety in the middle position was a VERY experienced hunter, and he was astonished when it happened. Afterward a gunsmith I know did considerable experimenting and found it happened more than once in a while with M70 Classics, and also came up with a solution.
I just tried it on the O'Connor Commemorative M70 Featherweight I bought this year, and the safety locked up in the middle position with bolt handle lifted slightly--but only after I pulled the trigger to "test" the safety, as many hunters feel compelled to do. I also got it to happen without pulling the trigger with the Gentry safety on my
.338 Winchester, but it wouldn't happen on my .375 H&H Mark X with Gentry safety.
I'll be very interested to hear what happens with your pre-'64's, because as noted earlier I couldn't get it to happen in a limited number of rifles.
