.460 Rowland technical questions

original: forums.1911forum.com
Retrieved: December 06, 2011
Last Post: November 06, 2011

ColtPistols
11-06-2011

I have almost settled on a Springfield GI hi cap as the foundation for this build. I am waiting on word whether or not this model utilizes a ramped barrel or has a ramped frame. Being a GI series I would guess it's a ramped frame. if it is than, although not recommended it should work with the basic conversion kit. I still have not figured out why the single stacks are recommended over doubles, but I think it should be ok.

On a slightly different route, I might be interested in haveing a different barrel turned into a .460 rowland. If this is even possible. Is the only difference the chamber is reamed longer than a .45ACP? If so I could have more options such as buying a longer barrel, or a bull barrel, or threaded barrrel etc, and have a 'smith ream it to appropriate dimensions. Then have a nice compensator fitted to the barrel. Will this work?


superdude
11-06-2011

Quote:
I have almost settled on a Springfield GI hi cap as the foundation for this build. I am waiting on word whether or not this model utilizes a ramped barrel or has a ramped frame. Being a GI series I would guess it's a ramped frame. if it is than, although not recommended it should work with the basic conversion kit. I still have not figured out why the single stacks are recommended over doubles, but I think it should be ok.

On a slightly different route, I might be interested in haveing a different barrel turned into a .460 rowland. If this is even possible. Is the only difference the chamber is reamed longer than a .45ACP? If so I could have more options such as buying a longer barrel, or a bull barrel, or threaded barrrel etc, and have a 'smith ream it to appropriate dimensions. Then have a nice compensator fitted to the barrel. Will this work? double stack magazines are not recommended, if i have this right from my previous contact with Clark Guns, because they move the rounds upward more slowly than single stack magazines. (all those extra rounds weigh more) this means there is less time to get the top round up far enough to be engaged by the slide as it moves forward. this is an issue because the 460 Rowland has such fast slide velocity, due in large part to the very powerful recoil spring used (24 lb) as well as the fast slide rearward movement due to the heavy recoil.

You're correct that the case dimensions are just a bit longer for the 460 Rowland than the 45 ACP. What I don't know is whether the barrel needs special hardening over that typical of the 45 ACP barrel to handle the high pressure of the 460 Rowland cartridge. Clack Custom Guns could answer that question for you.


Johnny handgun
11-06-2011

Just remember, better safe than sorry brother.


ColtPistols
11-06-2011

I read that the Rowland barrels have a .020 to .040 gap after the chamber before the rifling starts to lower the initial pressure. I have no idea what this means or if it's necessary, but would that mean that a .45ACP barrel could not safely be reamed to a longer chamber and then used for .460 Rowland?


ColtPistols
11-06-2011

Would heavier magazine springs help feeding from a double stack magazine or is this still going to cause too many jams?


Alland
11-06-2011

Quote:
I read that the rowland barrels have a .020 to .040 gap after the chamber before the rifling starts to lower the initial pressure. I have no idea what this means or if it's necessary, but would that mean that a .45ACP barrel could not safely be reamed to a longer chamber and then used for .460 Rowland?

If the chamber reamer did not have the correct throating profile for the 460 Rowland it would cause a problem unless the throat was lengthened with a throating reamer.


Alland
11-06-2011

Quote:
Would heavier magazine springs help feeding from a double stack magazine or is this still going to cause too many jams?

I have worked with double stack guns for a long time and magazine timing can be a problem with a normal 45. I don't think I would try to tackle one in 460 Rowland.


wc145
11-06-2011

I'm working on a dedicated .460 Rowland build and after speaking to the folks at Clark's I settled on a Para GI Expert for the base gun. The gentleman I spoke to told me that they did not recommend any one gun off the "approved" list over another for strength, fit, etc. So, since I was able to get a new GI Expert from Bud's Police Supply for $449 shipped, it got the nod. It's a nice gun, surprisingly well fit. I have my conversion kit already and will be sending the slide and barrel off to Clark's this week for their free fitting service. While that's being done I'll start collecting parts for the other changes I have planned. Should be a fun gun when it's all finished.


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