Details of the build from my friend and builder of the gun:
Now that the cat is FINALLY out of the bag, its time for me to chime in Big Grin
This was one of those builds that some said couldn't be done. But after a bunch of discussion, and a little bit of penciling things out on paper, I knew I could make it work. I suggested the .458 SOCOM, .450 Marlin or .458 X2 WM, but Cody really wanted a .45-70 SP to go along with his .45-70 rifle that he got as a grad present. This rifle has been one of his favorites, and if I could fulfill his wish of having a .45-70 SP, so be it.
Cody managed to get a donor gun lined up for the build, so at that point I was committed laugh Parts got ordered, and as soon as they started showing up, I went to work in the shop. There were several issues to address seeing how the .45-70 is a rimmed cartridge that measures out at .605".
I fit a M16 style Lapua extractor from PTG into a mock bolt to check fit and clearances. That all worked out as planned. Seeing how the .45-70 headspaces off the rim, and not a shoulder, a coned breach would be needed. the issue with that is that the extractor needed clearance to ride over the case rim throughout the bolt swing. That's where the semi-circle relief cut into the cone came into play. The web of the case is still completely encased in the chamber, so no case wall was going to be exposed.
I was also able to check feeding from the factory follower to make sure the case didn't hang up while chambering. - No issue there.
I opened up the bolt face on Cody's bolt from the standard .308 bolt face to .612", and machined the bolt for the Lapua extractor. Easy peasy!
Next up was to get the barrel chambered up and contoured. The APA brake that Cody supplied needed to be opened up from .338" through to .488" and I recut the threads on the tenon from 3/4-24 to 7/8-24 to give the .458" barrel a little bit more wall thickness.
A Lawton/Nosler bolt stop was added so the bolt could be pulled to eject loaded rounds. Cody went with EGW's HD 0 MOA 4 screw base, so the 4th hole got drilled and tapped through the receiver top.
I finally got her all buttoned up this week (Thanks for the patience Cody!)
and got out to the range today for test firing and barrel break in.
I'll admit on the first shot the pistol was at arms length not knowing what the recoil was going to be like? I was really surprised when the trigger broke! -Just a little muzzle hop! The APA brake is very effective. It also cleared all the cleaning patches and towels off the bench beside me. I was happy that I put the cap back on the solvent bottle too! It was laying on its side Eek Looked like a yard sale around the shooting bench laugh
Needless to say, everything functioned flawlessly, and the accuracy wasn't half bad Big Grin I know once Cody does some serious load development, who knows how well this gun will shoot? It will certainly put pork on the BBQ right now!
It was an honor and privilege to have built this SP for such a great friend. Cody, thanks for trusting me through this adventure bowdown
Hope you enjoy it!
-Mike
