I just bought a Charles Clarke rifle built by Joseph Lang. It's a SXS hammer gun with Jones Underlever. The rifle was originally built as a .450 but sleeved and reproofed in Birmingham in the 1930s to 7X57R. I have a drilling in 7X57R and a lifetime supply of RWS brass in the caliber. I don't see anything on the barrel flats regarding bullet weight from the photos. (I haven't received the rifle yet). What bullet weight would most likely have been employed in the 1930s in a British double rifle in this caliber? Any suggestions as to where to start?