1886nut
08-12-2013, 09:50 PM
Managed to locate some 500/450 no. 1 brass for an old WR falling block. Chamber cast and test chamberings of empty brass with some little squares of cellophane tape on the shoulder show that the brass is about .017 to .022 short on the shoulder. I've heard that Bertram is made this way because of the wild variations in old British chamberings. Barrel slug says .458 boolits should be OK, my plan was to make up some mild loads using Trailboss and the 70% rule.
My question is...do I need to fireform these cases out to the chamber dimension first, or can I just anneal the necks, load up with TB and fire away? If the latter, does it matter how far off the rifling I seat the boolits? As a side note, the rifling is polygonal, not lands and grooves.
My question is...do I need to fireform these cases out to the chamber dimension first, or can I just anneal the necks, load up with TB and fire away? If the latter, does it matter how far off the rifling I seat the boolits? As a side note, the rifling is polygonal, not lands and grooves.