Don't touch those chambers! Find or size brass to fit the chambers that were machined in the gun originally. If you need some help in doing that let me know. I hate to see a beautiful gun messed up by somebody reworking it unless you absolutely have to. I have quite an assortment of brass as well quite a few original boxes of vintage factory ammo & I will bet that the orignal old Norma that came in the 10 rnd boxes with the red label will fit your existing chambers. Where are you located? I just came out of the shop making up some 13mm brass for a H Scherping double rifle from the 1860's. Started out with some 24 ga brass shot shells & cut them down to 1.450 long, then formed them, then turned the diameters to fit the chambers. They are similar to a .577 Snider but a bit shorter & a .550 bullet dia.
m-4
