Anyone know what the twist rates were in the "golden era" of the early 1900s for the various .450s? I have this No. 1 with 26-inch barrel in .45-70 with a 1:20, and am entertaining ideas ...

The 450 Nitro Express 3-1/4" (Thin Rim of 1898), Grandaddy of all Nitro Express cartridges:

1:15" precisely = 1:381mm

That is why it was such an excellent performer from the get-go, kind of a fast twist for way back then.

Same 1:15" twist was also used in:

450 N0.2 N.E. 3-1/2" Eley

450/400 N.E. 3"

450/400 N.E. 3-1/4"

500 N.E. 3"

All stellar performers.

Thanks Rip.