I believe the 336 and the 1895 are the same frame. I know Regan Nonnemann builds 50 Alaskans on either so I would assume the 336 and the 1895 are the same frame. I know the 1895 has a larger ejection port.

JES builds the 405 on 336's from everything I've been able to garner.

Chronographs, bore scopes and pattern boards have broke a lot of hearts.