M.L McPherson uses case stretch. Because the locking lug is at the rear of the bolt in the 1895, a good length of metal is between the breech and the lock-up. That means high pressure stretches the steel and allows the bolt face to retreat enough to let the case stretch more than normal. So, cases ejecting suddenly longer would be his sign. I've never need to drive my 1895 that hard, but to each his own.
I keep a list of pressure signs, here