Originally Posted by gofastman
Can .40 be shot out of a stock 10mm EAA Witness?
It is not a good idea. Just like a 1911 and most other 10mm pistols, the firing pin is long enough to set off the round, even if it is in front of the extractor. This causes the case to slam back against the breech face, and sometimes results in case bulges and possibly ruptures. You'll also notice a spot where the case rim gets sheared off, as it's forced past the extractor (towards the rear) at high speed.
The Glock is the only gun I know of where this is a safe practice.
I will admit to doing this with my Witness back when I had one, to find out what it would do, and have never seen or heard of damage to a gun or shooter from it, but just judging from the appearance of the brass, I wouldn't do it any more.
In the Witness, when (not if) a round jumps the extractor, you'll see fired brass like this: