I've decided to undertake a new .460 Rowland conversion project since I have never been able to get the Glock conversions to run 100% with the heavy hard cast lead loads from Underwood and Double Tap. I picked up a second hand USP Tactical 45 V1 and found an extra threaded barrel and a 16x1mm LH thread compensator for an HK USP Tactical 45 pistol on Gunbroker. All the pieces are on the way.

I'm hoping that the reamer will cut the chamber on the HK barrel -- as the Germans are known for over-engineering things and may have super hardened the barrel... I was able to ream a factory USC barrel, so I am keeping my fingers crossed.

The USP Tactical pistol should be plenty strong enough to handle the pressures of the mighty .460 Rowland -- and I am hoping that stock recoil and magazine springs will run reliably, but I'll look to see if Wolf offers any extra power offerings.

The conversion should be simple -- ream the chamber to .460 Rowland specs, install the compensator and reassemble. I'll take plenty of photos of before and after -- as well as some range sessions with various loads and manufacturers of ammo over a Chrony.

I have the G30 and the G21LS in .460 Rowland, and I have previously converted a XD Tactical (premature unlocking caused bulges in the cases, so I abandoned it). In addition, I have a .460 Rowland barrel for my LAR Grizzly. I also have a carbine barrel for my USC/UMP sub gun in .460 Rowland -- so maybe I can do a little comparison to see which one gives the best velocity/power performance. I think the USP Tactical will be a winner with a great SA trigger and a 12+1 capacity. It should be a fun project.

Is it possible to ream a 1911 barrel to .460 Roland with no problems?

black shoe dog-850 said:

Is it possible to ream a 1911 barrel to .460 Roland with no problems?

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Yes - however, most conversions involve either a compensator threaded onto the barrel - or a ported barrel. The slide unlocking needs to be delayed and the slide velocity reduced in order for the conversion to work properly.

I have personally converted a 1911 to .460 Rowland without either a compensator or a ported barrel - but other actions were taken to delay unlocking and to reduce slide velocity. The strongest recoil and hammer springs were installed. Also, the typical beveled firing pin stop was replaced with a flat oversized firing pin stop to provide additional resistance and add dwell time.

I have a 6 inch threaded storm lake barrel .I'm thinking about getting a 6 inch slide for one of my frames and a comp for it.I just didn't know if reaming was possible.

Is is 6" plus the threads or 6" with the threads? If it includes the threads, a 6" slide won't allow the installation of the comp.

It is easy to ream the chamber by hand. You simply go slow and check the depth with a Rowland cartridge periodically to get the headspace right.

The 45 USP is a big bodied tough handgun. I have owned one and loaded it to 45 Super max load specs with 45 Suprer brass, without incident. If you change the recoil spring out to handle the additional pressure and unlocking speed it should digest the 460, that is designed for 1911 conversions, with little to no issue. But I am fairly positive that the H&K folks would not approve the idea as they like everything being overbuilt in my experiance.

I would reload and start with a mild load then work up to make sure everything went as planned. By the by, you might want to find a carbide reamer to make sure you do not have any reamer chatter on a hardened barrel cut plus keep the reamer well oiled.
Ed

It's 6 inch plus threads

Bill your Ex finds out about this, she will be taking out some life ins. on you, Since I have worked with you on some of you projects, how about putting me , to receive your life ins. Just my 2 cents jj

Oh, the judge let her keep the $1M life insurance policy... I'll have a target on my head for another 14 years or so. Fortunately, I'm 3,500 miles away and practice good situational awareness.

Ok - here's an update. I recd the firearm, extra barrel, comp, mag & recoil x-power springs, and a Manson finish reamer.

Unfortunately, the finish reamer wouldn't bite on the HK chamber. Not sure if it is hardened - or because of the polygonal rifling.

So, I had two options - use .45 Super brass and load ammo to .460 pressures, earmarking it for use only in the HK. Or, take the firearms and parts to a gunsmith and see if they could ream the chamber to .460 specs.

I decided to try option 2. Since Wild West Guns is here in Anchorage - and since they built Johnny Rowland's prototype pistol when he was developing the cartridge - I took everything over to Jim for them to make it happen.

Hopefully, they will call me in a week or so with a functional conversion.

I did learn something from Jim while I was there in the shop. For those who have done conversions on various pistols to .460 Rowland but yet have had issues with reliable feeding magazines, it may not be the magazine spring that is the issue. Jim says that because the brass is longer on the 460 Rowland cartridge, it may be necessary to trim or alter the feed lips just a bit on the magazines. As in shorten the feed lips just a bit.

I have them permission to alter the three 10-rd low capacity magazines I took over with the pistol if necessary - as I plan to get 12-rd mags if the conversion works.

My comp-free Rock Island conversion will feed 185gr loads - but not the 255gr HC loads. I'm going to alter one of my magazines on that pistol to see if it helps with feed reliability. I also plan to alter a Glock 21 magazine to see if that helps my long slide Glock as well.

More updates soon.


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That helps to have "the guy" that did the deed on the original prototype right in town.:thumb:
Ed

Alright, I was able to pick up the finished conversion from Wild West Guns today. They had to use a carbide reamer due to the HK hardened barrel. After conversion and assembly, they test fired it for function and it was 100 %. No modifications to the magazines were required - other than installation of extra-power springs from Wolff. I hope to get a range day with it soon to make sure the adjustable sights are zeroed in at 25 yards. I plan to try a variety of 460 Rowland loads that I have through it -- 185gr XTP, 230 gr GDHP, and 255gr HC lead with GC. I'll post some results photos as well as some Chrony information afterwards.

For now -- here are some pics of the converted HK USP Tactical in .460 Rowland

Good looking job. That 255 might not make a target round but for defense it is like a thrown brick. My Lyman mould 238 gr SWC casts at 255 and is a real pin bullet at 10 yards.
Ed

Interesting!

What issues were you having with the Glocks?

By the way, I have loaded regular ACP brass to 55-60k PSI in an appropriately built Glock 21.

I would think that the Glock might be a bit light for the heavy recoiling cartridges. Recovery from recoil is one of the most important considerations when developing defense loads, think effect and followup shots. What Flyand I were talking about is the H&K USP which is a big handgun. I shoot 45 Super and he has converted his to a Rowland.

I did not mention my big bullet gun is not the USP it is a 1911, all steel longslide, with 1 pound of steel added under the grip panels and weighted springs and buffers added to the slide, then low pressure loads that barely function the gun. With a range in my back yard I developed this setup using a timer and pins to achieve the fastest times to clear tables.
Ed

I have a couple thousand rounds through my G21 ranging from Super levels to .460 +P++. My records were a 250gr XTP at 1440fps, and a 200gr XTP at 1660fps (yes, over 1200 ft-lbs). Using a shot timer, I was able to consistently run .33-.35 splits on a 5 yard target with those max-level loads.

Also, the Glock21 slide is 16oz vs 13oz for a 1911, or about 30% heavier.

But I am still curious to find out what actual malfunctions he was having with the G21. Based on his comments about needing stronger mag springs, it sounds like the gun was under-compensated, which is a common symptom of guns built with the hopes of shooting both .460 rowland and factory-level .45 ACP.

Might be, I have no experience with the 21 conversion. You will need a response by Flyand.
Ed