How to change barrels on a Ruger MkII?

K31Fan · January 3, 2009, 02:39 AM

I just acquired an old Ruger MkII with a damaged muzzle crown. All the other parts are fine, so I'd like to remove the existing barrel and replace it with a better one. I can find lots of places online selling match bull barrels, but no instructions for removing and replacing the barrel. I take it a vice and some kind of wrench are required; does anyone know more? Thanks for any help.

Bill DeShivs · January 3, 2009, 03:08 AM

I would just recrown the existing barrel.

K31Fan · January 3, 2009, 03:37 AM

That's not the only problem the barrel has... I just took the gun apart to look at it and it looks like the breech has been damaged by dry-firing; there's a nick in the top of the barrel and a burr sticking into the chamber. The guy I got it from said it wasn't feeding correctly and it looks like this is the reason. I don't know if there's a way to fix that; even if you removed the burr there'll still be a nick in the top that may prevent the firing pin from properly crushing the cartridge rim.

Slopemeno · January 3, 2009, 08:08 AM

Brownells sells a tool that will iron out that dent. While youre at it, you can order the pin that is missing from your Mk-II bolt that was meant to keep the firing pin from hitting the breechface.

Removing the barrel isn't too hard, but you need a barrel vice with fitted jaws. Keep in mind you'll need to fit and "index" the barrel so that the front sight and feedramp are at 0 and 180 degrees when the barrel is tight in the receiver- in my opinion something that should be left to a gunsmith who has the tools and training.

Like Bill said, I'd just recrown it. You'll be surprised how accurate one of these guns is stock.

Scorch · January 3, 2009, 02:00 PM

I rebuilt a basket case Ruger Mark II 22 Automatic Pistol last year. The guy who owns it said it needed "a little work". I had never seen a pistol in worse shape. The frame was rusted, rear sight was missing, several pins had been replaced with brazing rod, the trigger was bent, the grips were broken and glued back together, and someone had drilled holes in the grip frame for some unknown reason. It took $100 worth of parts, 7 or 8 hours of polishing, recrowning, bluing, reassembly to get the gun back into service. Off a bench, the pistol fired 2" groups at 25 yds with cheap 22 ammo. So, long story short, unless there is something drastically wrong with the pistol, it likely shoots better than you may think. But it's your pistol, you can buy a new barrel and have it fitted. Any competent gunsmith can do the job.

James K · January 3, 2009, 08:09 PM

Fitting a Ruger barrel is trickier than one might think. The reason is the way they are installed in the factory. Ruger makes the barrel, complete with front sight base and feed ramp, all in one piece, and screws it into a piece of threaded tubing. Then, using the feed ramp as a reference point, they machine the ejection port, the magazine opening, and the rest of the receiver.

That is fine, but it does mean the barrel and receiver are mated to each other and require more fitting than the usual barrel-receiver combination.

Jim

January 3, 2009, 02:39 AM	#1
K31Fan Member Join Date: August 5, 2007 Posts: 20	How to change barrels on a Ruger MkII? I just acquired an old Ruger MkII with a damaged muzzle crown. All the other parts are fine, so I'd like to remove the existing barrel and replace it with a better one. I can find lots of places online selling match bull barrels, but no instructions for removing and replacing the barrel. I take it a vice and some kind of wrench are required; does anyone know more? Thanks for any help.

January 3, 2009, 03:08 AM	#2
Bill DeShivs Senior Member Join Date: April 7, 2006 Posts: 10,979	I would just recrown the existing barrel. __________________ Bill DeShivs, Master Cutler www.billdeshivs.com

January 3, 2009, 02:00 PM	#5
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	I rebuilt a basket case Ruger Mark II 22 Automatic Pistol last year. The guy who owns it said it needed "a little work". I had never seen a pistol in worse shape. The frame was rusted, rear sight was missing, several pins had been replaced with brazing rod, the trigger was bent, the grips were broken and glued back together, and someone had drilled holes in the grip frame for some unknown reason. It took $100 worth of parts, 7 or 8 hours of polishing, recrowning, bluing, reassembly to get the gun back into service. Off a bench, the pistol fired 2" groups at 25 yds with cheap 22 ammo. So, long story short, unless there is something drastically wrong with the pistol, it likely shoots better than you may think. But it's your pistol, you can buy a new barrel and have it fitted. Any competent gunsmith can do the job. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

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January 3, 2009, 03:37 AM	#3
K31Fan Member Join Date: August 5, 2007 Posts: 20	That's not the only problem the barrel has... I just took the gun apart to look at it and it looks like the breech has been damaged by dry-firing; there's a nick in the top of the barrel and a burr sticking into the chamber. The guy I got it from said it wasn't feeding correctly and it looks like this is the reason. I don't know if there's a way to fix that; even if you removed the burr there'll still be a nick in the top that may prevent the firing pin from properly crushing the cartridge rim.

January 3, 2009, 08:08 AM	#4
Slopemeno Senior Member Join Date: January 19, 2007 Posts: 2,663	Brownells sells a tool that will iron out that dent. While youre at it, you can order the pin that is missing from your Mk-II bolt that was meant to keep the firing pin from hitting the breechface. Removing the barrel isn't too hard, but you need a barrel vice with fitted jaws. Keep in mind you'll need to fit and "index" the barrel so that the front sight and feedramp are at 0 and 180 degrees when the barrel is tight in the receiver- in my opinion something that should be left to a gunsmith who has the tools and training. Like Bill said, I'd just recrown it. You'll be surprised how accurate one of these guns is stock.

January 3, 2009, 08:09 PM	#6
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Fitting a Ruger barrel is trickier than one might think. The reason is the way they are installed in the factory. Ruger makes the barrel, complete with front sight base and feed ramp, all in one piece, and screws it into a piece of threaded tubing. Then, using the feed ramp as a reference point, they machine the ejection port, the magazine opening, and the rest of the receiver. That is fine, but it does mean the barrel and receiver are mated to each other and require more fitting than the usual barrel-receiver combination. Jim