Ruger Forum

45 Auto Rim

This is a discussion on 45 Auto Rim within the Ruger Single Action forums, part of the Pistol & Revolver Forum category; On a 45 ACP cylinder from a NMBH, how much has to be removed from cylinder to make clearance (head space) for the 45 AR ...


Go Back   Ruger Forum > Pistol & Revolver Forum > Ruger Single Action

Reply
 
LinkBack Thread Tools Display Modes

Old November 29th, 2010, 06:55 PM   #1
 
Join Date: Jan 2008
Location: North Central Montana
Posts: 352
38-55 is on a distinguished road
45 Auto Rim

On a 45 ACP cylinder from a NMBH, how much has to be removed from cylinder to make clearance (head space) for the 45 AR cartridge?



38-55 is offline  
Advertisements
Old November 29th, 2010, 07:47 PM   #2
Retired Gunsmith
 
Iowegan's Avatar
 
Join Date: Aug 2006
Location: Blair, NE
Posts: 8,784
Iowegan has a spectacular aura aboutIowegan has a spectacular aura about

Awards Showcase

38-55, The rim on those 45 Auto Rim cases are pretty thick ... typically .09". Add .01" for headspace ... for a total of .1". Measure the gap between the rear of the cylinder face and the recoil shield. Subtract that measurement from .1 inches to find out how much metal you have to remove ... typically .030".

Just a question .... why not use Starline Cowboy 45 brass or cut down 45 Colt cases. It has the right rim thickness and right length to work perfect in a 45 ACP cylinder. No modification of the gun is required plus the cases use the same exact loading recipes as 45 ACP ammo.
Iowegan is offline  
Old November 29th, 2010, 08:48 PM   #3
 
Join Date: Apr 2009
Location: SW Ohio
Posts: 568
Dale53 is on a distinguished road
38-55;
Iowegan is giving you excellent advice. I have the .45 Cowboy Special brass and it works perfectly well. The advantage of the .45 Cowboy Special over cut down .45 Colt cases is that cut down Colt cases often thicken towards the bottom and can interfere with the bullet base. The .45 Cowboy Special brass has the same rim as the .45 Colt with the capacity of the .45 ACP and .45 Auto Rim.

I have a Ruger SS Bisley .45 Colt and .45 ACP convertible and find uses for all three cases (.45 Colt, .45 Cowboy Special, and .45 ACP).

Dale53
Dale53 is offline  
Old November 30th, 2010, 04:58 AM   #4
 
Rodfac's Avatar
 
Join Date: Jun 2009
Location: Northern KY
Posts: 536
Rodfac is on a distinguished road
Iowegan...great advice...I've loaded .45 AR and ACP for years and never thought of that simple expedient. Rodfac
Rodfac is offline  
Old November 30th, 2010, 01:26 PM   #5
 
Join Date: Jan 2008
Location: North Central Montana
Posts: 352
38-55 is on a distinguished road
Good point, before I go searching; is the Starline 45 Cowboy Special brass a regular production item or do I have to make it?
I also shoot a Colt New Service in 45 ACP, so I use the AR cases there too. The 45 Colt Cowboy brass would not work in the New Service, I'm thinking head space?
Wright-rong, I'm so confused! Shoulda hada V8!!!!!!!!
38-55 is offline  
Old November 30th, 2010, 01:42 PM   #6
 
Maximumbob54's Avatar
 
Join Date: Oct 2010
Location: JAX, FL
Posts: 3,136
Maximumbob54 is on a distinguished road

Awards Showcase

WHAT? Someone knows where .45 Colt brass is? Where it isn't on permanent Taurus Judge gone crazy with sales kind of back order? I bet it is easier to find .45 Auto Rim right now.
Maximumbob54 is offline  
Old November 30th, 2010, 04:45 PM   #7
Ed Mann
 
edlmann's Avatar
 
Join Date: Jun 2009
Location: lovely downtown Central Florida
Posts: 394
edlmann is on a distinguished road
Quote:
Originally Posted by Iowegan View Post
Just a question .... why not use Starline Cowboy 45 brass or cut down 45 Colt cases.
Already have several hundred .45AR cases.

ETA: Because none of the other kids can.

Quote:
Originally Posted by Iowegan View Post
It has the right rim thickness and right length to work perfect in a 45 ACP cylinder. No modification of the gun is required plus the cases use the same exact loading recipes as 45 ACP ammo.
Think the idea is that the Cowboy round is that it allows .45ACP loads/ballistics in a .45LC cylinder. Don't know if these would work in a .45ACP cylinder. This would mean changing the headspacing from the case mouth to the rim. Might work as is, might not. The ACP cylinder would have less of a jump before hitting the throat, I suppose. And if they would work, why not just use ACP brass? The Cowboy Special brass would allow use of a roll crimp in an ACP cylinder without screwing up the headspacing, but I don't use any AR/ACP loads that require a roll crimp. In any case, this is the first mention I've seen about using the Cowboy Special brass in an ACP cylinder.

Last edited by edlmann; November 30th, 2010 at 04:56 PM.
edlmann is offline  
Old November 30th, 2010, 05:02 PM   #8
Ed Mann
 
edlmann's Avatar
 
Join Date: Jun 2009
Location: lovely downtown Central Florida
Posts: 394
edlmann is on a distinguished road
Quote:
Originally Posted by 38-55 View Post
Good point, before I go searching; is the Starline 45 Cowboy Special brass a regular production item or do I have to make it?
Order .45 Cowboy Special brass here.
edlmann is offline  
Old November 30th, 2010, 05:14 PM   #9
 
Join Date: Jan 2008
Location: North Central Montana
Posts: 352
38-55 is on a distinguished road
What is the head stamp on "45 Cowboy Special" cases?
38-55 is offline  
Old November 30th, 2010, 05:50 PM   #10
Retired Gunsmith
 
Iowegan's Avatar
 
Join Date: Aug 2006
Location: Blair, NE
Posts: 8,784
Iowegan has a spectacular aura aboutIowegan has a spectacular aura about

Awards Showcase

edlmann, You got it reversed. The Cowboy brass is made to fit perfectly in a 45 ACP cylinder. Instead of headspacing on the case mouth like a 45 ACP case, it headspaces on the rim. You can use these same cases in a 45 Colt cylinder but because of the extra long chamber, quite a bit of pressure is lost so velocity suffers as does accuracy.

These cases were designed specifically for 45 ACP cylinder and will work just fine on S&W Mod 25s or Colt New Service without moon clips. Turns out, the Cowboy brass will also headspace like a normal 45 ACP case on the case mouth but it does increase headspace a token couple thousandths of an inch.

The headstamp is "COWBOY 45 SPECIAL"
Iowegan is offline  
Old November 30th, 2010, 06:31 PM   #11
 
Yurko's Avatar
 
Join Date: Jul 2010
Location: Eastern Wisconsin
Posts: 445
Yurko is on a distinguished road
Quote:
WHAT? Someone knows where .45 Colt brass is?
Cabela's has Winchester & Remington available.
Starline is on backorder of course
Yurko is offline  
Old December 1st, 2010, 07:25 AM   #12
Ed Mann
 
edlmann's Avatar
 
Join Date: Jun 2009
Location: lovely downtown Central Florida
Posts: 394
edlmann is on a distinguished road
Quote:
Originally Posted by 38-55 View Post
What is the head stamp on "45 Cowboy Special" cases?
edlmann is offline  
Old December 1st, 2010, 07:41 AM   #13
Ed Mann
 
edlmann's Avatar
 
Join Date: Jun 2009
Location: lovely downtown Central Florida
Posts: 394
edlmann is on a distinguished road
Quote:
Originally Posted by Iowegan View Post
edlmann, You got it reversed.
Unfortunately, it wouldn't be the first time.

I did have help, though.

Quote:
Originally Posted by Iowegan View Post
The Cowboy brass is made to fit perfectly in a 45 ACP cylinder. Instead of headspacing on the case mouth like a 45 ACP case, it headspaces on the rim. You can use these same cases in a 45 Colt cylinder but because of the extra long chamber, quite a bit of pressure is lost so velocity suffers as does accuracy.
These cases were designed specifically for 45 ACP cylinder and will work just fine on S&W Mod 25s or Colt New Service without moon clips. Turns out, the Cowboy brass will also headspace like a normal 45 ACP case on the case mouth but it does increase headspace a token couple thousandths of an inch.
I suspect everything you say is correct. My source of information has been Cowboy45Brass dot com. I've been all over the web site and I can find no mention of using this brass in a .45ACP cylinder. Glad to hear it works in the ACP as I also have a Model 25 I had shortened to 4" back in the day before the factory did that. It's why I have the AR brass.

It also seems that if the headspace is increased using the Cowboy brass, then it's either the case length is a bit off, or it is headspacing on the rim instead of the mouth. I'll stick to the AR case for now since I'm already pretty well into that. I just want to be able to use the same loads in my NMBH.
edlmann is offline  
Old December 1st, 2010, 09:05 AM   #14
Retired Gunsmith
 
Iowegan's Avatar
 
Join Date: Aug 2006
Location: Blair, NE
Posts: 8,784
Iowegan has a spectacular aura aboutIowegan has a spectacular aura about

Awards Showcase

edlmann, When Starline first released the Cowboy brass, they had a nice write-up on its intended use. Seems Adirondack Jack bought up a bunch of it but got the intended use backwards and it spread throughout the Internet. Using short brass in a long 45 Colt chamber does not work very well because the "free bore" is the diameter of the case (.480") and the bullet is .452". So ... the bullet travels about .4" in a .028" oversized hole. This will allow a lot of pressure loss and will result in lower velocity plus the potential accuracy loss.

The length of the Cowboy brass is set where the case mouth almost touches the internal chamber stop when the rim contacts the cylinder face (ie Blackhawk 45 ACP cylinder). When used in a cylinder designed for moon clips (ie S&W Mod 25), the case mouth will contact the internal chamber stop, leaving about a .028" gap between the rim and cylinder face and will function exactly like a 45 ACP case with an extra .002" of headspace ... basically negligible. Because the Cowboy brass has a rim, the ejector on a DA revolver will work without using moon clips ... just like Auto Rim cases.

With a SA revolver chambered for 45 ACP, there's really no advantage using rimmed cases because the ejector rod pushes just one case at a time and focuses on the inside of the case, not the rim. CASS shooters like the rimmed cases because they are "period correct" but they do not shoot any better ... just cost more.

I experimented with both "cutoff" 45 Colt cases and Cowboy cases. The cutoff cases have a tapered web that wouldn't let a flat base bullet seat properly, whereas the 45 Cowboy brass have a non-tapered web and will allow flat base bullets to seat to the proper depth. I found some 230 gr LRNs with a tapered base that worked quite well in the cutoff cases. I loaded to the same specs as 45 ACPs (6 gr of Unique). With the same 230 gr LRN bullets in both ACP and Cowboy cases fired from my 7 1/2" Blackhawk, velocity was nearly identical (about 900 fps). Accuracy was about the same with both.

With the Cowboy loads in my 45 Colt cylinder (same gun), velocity dropped to about 650 fps and groups spread quite a bit. Although they do shoot in the 45 Colt cylinder, I would not waste my time with them.

I would never recommend modifying a Blackhawk cylinder just to use 45 Auto Rim brass. People that buy 45 AR brass are reloaders and could just as easily load 45 Colt cases if they want the rim. ACP cases may not have a rim but they are way more available at a much cheaper price.
Iowegan is offline  
Old December 1st, 2010, 11:26 AM   #15
 
Join Date: Sep 2006
Location: Port Republic, Maryland, USA.
Posts: 372
TomC is on a distinguished road
I have several NMBHs with .45 ACP cylinders modified to use .45 AR brass. I did this a few years ago before the .45 Cowboy became available. I have .45 AR brass and a couple of S&W .45s that I like to shoot. The ammo is interchangeable and I load it on the same die setup in my Dillon 550 as my .45 ACP.
I have a lot of scrounged .45 ACP brass. The case length tends to vary all over the map. This isnít an issue with a 1911, or when using moon clips in a S&W, but it can become an issue when shooting with a NMBH or a S&W without clips. I have installed longer firing pins in my 625s, but I canít easily do that in my NMBHs. I also prefer the feel of the cylinder cycling with the .45 AR over the same gun with .45 ACP.
TomC is offline  
Reply

  Ruger Forum > Pistol & Revolver Forum > Ruger Single Action



Search tags for this page
.45 auto rim
,
.45 cowboy special brass
,

45 auto rim

,
45 auto rim blackhawk
,
45 auto rim forum
,
45 auto rim in rugers
,
adirondack jack's trading post
,
blackhawk 45 auto rim
,
can 45 auto rim be used in a 45 colt gun
,
ruger 45acp cylinder cut for auto rim for sale
,
ruger blackhawk .45 auto-rim
,
ruger blackhawk 45 rim
Click on a term to search for related topics.

Thread Tools
Display Modes


Similar Ruger Forum Discussions
Thread Thread Starter Forum Replies Last Post
Auto's firefirst Ruger Rimfires 9 July 27th, 2011 04:38 PM
Auto Indexer? metweezer Reloading 5 July 11th, 2011 05:00 PM
Accurate 9mm auto rman Pistols & Revolvers 26 April 28th, 2009 11:36 AM
.357 auto? HIPCHIP Pistols & Revolvers 3 February 27th, 2009 06:44 AM
LCP .380 Auto +P ??? billymac Ruger Pistols 3 January 14th, 2009 03:10 PM

Top Gun Sites Top Sites List  
Powered by vBulletin 3.8.7
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.1
Copyright © 2006 - 2014 Ruger Forum. All rights reserved.
Ruger Forum is a Ruger Firearms enthusiast's forum, but it is in no way affiliated with, nor does it represent Sturm Ruger & Company Inc. of Southport, CT.