I am restoring a "family heirloom" side by side, hammer action, 12g.
Unfortunateley I am not quite sure of the correct terms, but I will describe it and maybe it makes sense.
When you push the breech locking lever top one side, this acts on a "slab" of metal that moves forwards and backwards underneath the barrels to engage with a lug that is on the bottom of the barrels.
The edge of this 'bar' or 'slab' has worn over the years because when the shotgun is closed, the lug on the barrels is slightly angled to push the bar open - the classic 'snap the gun shut' action we all know. Because of the wear, the rear face of the barrels do not sit tight against the action - in effect the barrels 'rattle' and I certainly dont want to fire it like this!
So I need to re-make this bar. Easy enough job using a milling machine, or by hand filing, but my question is what steel do I use? or should I use a mild steel but then case harden it?
The precise design of the bar means that the entire force it has to withstand during a discharge is taken through a cross section approximately 1/8 x 1/4 inch. I dont want to make it brittle by hardening it but I dont want the same fault to re-appear in a couple of years through wear of the unhardened metal.
ANy experts care to comment?
(By the way, I will be having the gun proofed after repair, before using it!)