Looking for some insight into moving to hand loads for an A. Mulcaz back action hammer combo gun in 8x57JRS x 20 gauge. Through some trials and tribulations, the gun is back to making smaller groups at 200 yards with factory SB and PP 196 grn loads through a Zeiss 2.5-10x50 Diavari scope.
I’d like to work up loads for two bullets: the Sierra 175 grn ProHunter and Speer 200 grn
Hot-Cor, and mainly want to get a good cartridge overall length.
In various websites and Cartridges of the World the COL is listed from 2.835 to 3.17 depending on the projectile.
The short answer for a COL is likely to just follow those recommendations from the powder or bullet companies and move on.
However, in the newest edition of Shooting the British Double Rifle (understood this is an Austrian combination gun, but still…), on pages 107 and 108, Graeme Wright describes what seems to be a good method of developing a COL with different projectiles, as determined by their ogive and how far out of the cartridge case the bullet may protrude to minimize the jump to the rifling.
When I do this with the 175 and 200 grn bullets above, I get 3.35” and 3.39”. The bullets would barely seat in the case at those lengths.
So, I must have a very long chamber throat.
Any advice or thoughts on the above? Just follow the bullet/powder manufacturer’s instruction?
As always, thank you for the insight and advice given on this website!
