I got mine in the marlin x7 pattern from mcgowen.

I have been able to use a couple of savage barrels on the x7, but you have to be careful that the chamber is not too deep. If it is, you will hit the bolt face with the back of the barrel before coming up tight on the headspace gauge. If the 783 is the same as the x7, it probably has the same concern.

Last edited by vabowhntr; 06/12/20.