Hello Pukka...
Sorry for the late reply but I've been so busy working on my house everything else has fallen behind. This will sound strange, but I'm not sure where that gun is right now. It's probably in the "gun storage" room at may shop, in which case I'll measure it the next time I'm in there..As an interesting aside, Erik Goldstein (Colonial Williamsburg) told me it's the only Ordnance marked Humphrey Pickfatt lock he's ever seen. If I remember correctly, the barrel is marked AR...consistent with the lock and the barrel both coming from what must have been a very old gun when it was restocked.
Oh, and I think the mittens were made with a hole for the trigger finger...I've had mittens like that at one time.