.460 Rowland conversion question

[CLP]

I'm really just curious. I understand the ability to shoot 38 Special out of a 357 Magnum because they headspace off the rim.
I was looking at http://www.brownells.com/handgun-pa...auto-460-rowland-conversion-kit-prod5003.aspx and started reading about this cartridge. Apparently, you can still shoot 45 ACP and 45 ACP +P once this conversion is installed. The 460 Rowland has a case length that's longer than the 45 auto to prevent it from being loaded in a gun with a 45 ACP chamber- this could meet with really bad results given that the Rowland's pressure is almost 3X that of the 45 Auto. What I can't figure out is how you can shoot 45 Auto in a pistol that's had this conversion since it's supposed to headspace off the case mouth. Being shorter than the 460 Rowland, how does it headspace? Couldn't the 45 ACP cartridge be seated so far in the chamber that the firing pin couldn't ignite the primer?

 

[Havok7416]

In that case, the ACP round is headspacing off the extractor. It's not just going to plunge into the chamber.

 

[rcmodel]

The shorter .45 ACP case is held to the rear by the extractor hook.
Close enough to the breech face for 1911 inertia firing pins to easily reach the primer.
They have about 1/4" extra travel available, if thats what it takes to reach the primer!

Not sure how reliable that would work with striker fired guns though!

And certainly not the best way to do it for precision accuracy.

I believe I would just keep an extra .45 ACP barrel & recoil spring handy if I wanted to switch back to .45 ACP.

You gotta take the slide off to put the lighter spring back in anyway.

It works in .460 Rowland chambered .45 ACP revolvers because the rounds are head-spaced by moon clips in the cylinder.

 

[CLP]

Thanks, that makes perfect sense. I've been reading that some FMJ bullets, especially in the 185gr weight range, don't work well at Rowland velocities. I'm gonna have to check my reloading manuals and read more. Anyone know how well hardcast bullets perform in this cartridge?

 

[rockhopper46038]

Georgia Arms loads a 185gr JHP at 1550 fps that runs well in my .460 Rowland. I haven't played around with reloading the cartridge yet to suggest any other options.

 

[barnbwt]

I'd have to assume firing the short round isn't good for the extractor, either (same as I've been told for 380 in 9mm, etc.)

TCB

 

[MachIVshooter]

I'd have to assume firing the short round isn't good for the extractor, either

Meh, a lot of guns headspace with the extractor even when the correct cartridge is used. The action of yanking a case from the chamber and being the fulcrum as it is violently ejected from the gun creates a lot more stress than the FP dimpling soft brass.

(same as I've been told for 380 in 9mm, etc.)

.380 in a 9mm ain't just a headspace issue; the .380 case has a thinner rim and smaller outside diameter than a 9x19mm.

 

[rcmodel]

+1

The whole .380 ACP case is straight back from the case mouth, and everything about it is smaller & shorter then the tapered 9mm case.

The bullet dimeter is the only thing about it that is the same.

You Do Not shoot .380 in a 9mm because of it head-spacing on the extractor hook damaging it.
You Do Not shoot .380 in a 9mm because its a completely different size cartridge all the way around!

rc

 

[WC145]

If you want to shoot .45ACP just swap your original barrel back in.

 

[hardluk1]

Don't shoot 45 , P+ or super in a 460 barrel. 45auto rest on the case mouth and should not rely on the extractor to keep it held back. Reload 460 to lower pressure or swap barrel and recoil spring

 

[TRX]

You have your old .45 barrel and recoil spring; just slide them back on when you want to shoot .45.

The main thing that has stopped me from going to the Rowland is scrabbling after the ejected brass after I'm done. As a reloader, it nearly kills me to lose a piece of brass. (you wheelgun guys can just **** now because I'm not listening to you)

 

[Robert101]

Not my practice....... but what I have heard of people doing is to handload the 45 Automatic close to the same length as the .460. By this I mean, to test fit the bullet out to and as close to the lands as possible. Sort of having the 45 Automatic fit into the chamber up against the lands, thereby, reducing the play in the chamber. Like I said, not my practice this is only what I read on the internet. Yeah, yeah, I know.