Loading heavy SWC's in NMBH 45acp cylinder?

[Bruce in WV]

I have a bunch of 280gr .454 SWC's I want to shoot in the 45acp cylinder of my NMBH. I want to load them to 900 - 1,000fps velocity.
I think I need to seat the forward driving band at the forward edge of the case mouth and apply a taper crimp since the 45acp headspaces on the case mouth. That means a compact amount of powder to avoid compressing the load.
I would appreciate suggestions for a 45acp load using this bullet in the NMBH.

 

[Bruce in WV]

I don't think I'm going to try this. I found a good discussion on another site that convinces me this can't be done safely.

https://castbulletassoc.org/forum/thread/pressure-in-45-acp-revolvers/

 

[azleite]

That's a interesting article. I have a standard Blackhawk. I've just shot target loads out of the ACP cylinder- 4.9 grains of HP38 under a 200 grn lasercast SWC @ 1.214". I seat them that deep so they chamber without protruding & tieing up the gun. Never any signs of excessive pressure + their super accurate. I guess my point is I didn't think anyone else was using SWC's in the ACP cylinder

 

[Enigma]

You could, probably, develop a SAFE load for those bullets in that cartridge, but not at the velocity that you desire. I think you reached a wise conclusion.

 

[snakeeyes4445]

With my .45 NMFT Combo, such a round would not even chamber. My throats gauge at .451, so the forward part of such a round would not allow for cartridge seating at all. I am leaving the ACP throats alone for jacketed bullets and sending the Long Colt cylinder out for honing to accept the .452 SWC or other more powerful load. Points of impact will be fun to coordinate for the two types of loads in the same gun.

 

[Mobuck]

I'd say you made a good choice for the sake of yourself and your gun.

 

[Dale53]

I have both Smith 625's and a Ruger SS Bisley .45 ACP/.45 Colt Convertible. Brian Pearce has excellent information on loading the RCBS 45-270-SAA bullet in the .45 Auto Rim (280 grs. in his alloy) in the Handloader Magazine #254. I have a bit of experience loading heavy bullets in the .45 ACP revolvers. I feel MUCH more comfortable stopping with the Lyman 452424 (250 grs.). You can safely get to 900 fps. without issue.

NOTE: In the Smith 625's I use the .45 Auto Rim case and crimp in the crimp groove. In the Ruger single action, I use the rimmed .45 Cowboy Special (same case capacity as the .45 ACP but with a .45 Colt rim). It headspaces correctly in the single action (on the rim) and allows you to crimp in the crimp groove allowing the proper length. Pressures go up rapidly in the .45 ACP case when the overall length is shortened.

Both the 625's and the Ruger Bisley's cylinder throats are at .4525". My bullets are home cast and sized to .452". Alloy is WW's+2% tin.

FWIW
Dale53