It has arrived. I may post some photographs on another thread. But, to keep to the matter in hand, I have made a chamber cast as below.

I tried bathroom silicone sealant. Don't! Tried sulphur but melting powder was vv smelly and the cast would not remain whole. This one was done with paraffin wax after oiling the chamber and preheating the metal with a paint stripper. Worked a treat, kept topping it up as it shrank on cooling and inserted a screw to hold one end. Popped it in the freezer for 2 hours after it had set then it came out with no problems at all. Another time I will add a wax crayon for colour.

I have marked where the 42 case should end and the 58 case should end. The apparent end is at 54mm but there is little discernible change as it becomes the throat with the rifling becoming apparent at 63mm. There is only a short shoulder of about 3,5mm.

Would this match to the 11,15x58R rechambering of the 1867 11,15x42R? The rear sight is still graduated to 1400 paces so is not updated.

Attachment 54570Attachment 54571