Ballistics by the inch

It’s like flinging thunderbolts.

You may remember that I have a small bit of an obsession with the .460 Rowland cartridge.  Ever since we tested it for BBTI, I’ve wanted one. As I noted in one of those articles:

I said it before and I’ll repeat it here: if you carry a .45, you should instead be carrying a .460 Rowland.


So, early this year I put in an order for a .460 Rowland conversion kit for a new Gen 4 Glock 21.

I’m planning on doing a full formal review of the kit and the resultant gun, but I thought I’d share some of my experience so far. Why “so far”? Well, because I haven’t worked out all the minor kinks yet.

OK, first thing: it didn’t just take the 3 weeks for delivery which was promised. It wasn’t even 3 months. It was almost six months. And a buddy of mine who ordered his before I ordered mine still hasn’t gotten his. So, there’s that.

Second, and part of the reason for the delay, I didn’t receive a new barrel which was marked .460 Rowland. Rather, I got what looked like a standard Wolff .45 barrel. But it had indeed been rechambered to handle the .460 Rowland cartridge. Before I received the kit I got an email advising me of this problem, and I figured I could just roll with it. This is what I got in the kit:

.460 Rowland Conversion Kit.

.460 Rowland Conversion Kit.


Going clockwise from the top: That’s the threaded barrel, a screw-on compensator, spring assembly adapter, small serving of red loc-tite, and the heavy spring assembly (which is actually the Gen 3 design, but with the adapter works just fine in my Gen 4).

As advertised by .460 Rowland, the conversion takes like 30 seconds. If you can field strip your Glock, you can do the conversion. I’ve opted for using blue loc-tite rather than red, since it still works well but allows me to remove the compensator easily if I need to.

How does it work? Well, I’ve taken it out to the range several times now, shooting both factory rounds as well as my own reloads. Doing some informal chrono tests, I have gotten exactly the kind of performance promised and expected. The Buffalo Bore 230gr JHP were right at 1300 fps. 200gr RNFP reloads were at 1380 fps, and 185gr XTP (JHP) reloads were at 1410 fps. And those reloads are actually fairly mild — just 12.5gr of Longshot powder — based on what data I’ve seen, I could probably push that to 13.5gr without any risk. (Don’t consider this an endorsement — do your own research, and work up your own loads using published data and standard safety practices.)

Shooting the .460 loads out of the Glock is like shooting a .44 magnum (which I have a fair amount of practice with), but having 13 rounds on tap. Seriously, it’s like flinging thunderbolts with each shot. And the recoil is surprisingly manageable, though I’m not someone who is very recoil shy.

So, why did I say I was still working out the kinks?

Well, there’s a problem with the magazines. Here’s what happened after the first outing:

Glock 21 magazine

Glock 21 magazine


Look closely on the left side of that magazine, and you’ll see that there’s a tab which has been torn a bit loose and pushed forward. That’s from the force of the .460 cartridges slamming forward. At about this point the magazine would no longer release or insert smoothly. That was after my first outing, with about 60 .460 Rowland shots fired. And actually, I damaged two magazines to that extent with those 60 rounds.

So after that first outing, I took a Dremel tool to the magazines and cut away about 1/8″ of material, and flattened the whole face back into position. Today I took those two magazines back out to the range, and ran about another 50 rounds through the gun using the two of them. Here’s one of them after today’s outing, next to a new unaltered magazine:

Two Glock 21 magazines.

Two Glock 21 magazines.


More problems. This time, the little metal tab snapped off, as well as distorting the face of magazine again. Clearly, I need to sort out how to fix this.

Two other things I want to mention. One, I tried shooting standard .45ACP cartridges out of the .460 Rowland conversion. They work wonderfully. Seriously, there’s almost no recoil, the gun cycles just fine (with my mild reloads as well as factory +P self defense ammo), and there’s no accuracy loss that I could determine casually shooting the gun. So, that’s a plus.

But the other thing? Heh — take a look at what happened with my front site today:

Glock 21

Glock 21

Yeah, it really shouldn’t be facing that way, nor sticking up quite so much. But I can fix that easily enough.

If you have thoughts on how I can correct the magazine problem, I’d love to hear ’em.


Jim Downey

September 23, 2013 - Posted by | .45 ACP, .460 Rowland, Anecdotes, Discussion. | , , , , , , , , , , , , , , , ,


  1. […] weeks back I put up a post about my preliminary experiences with a .460 Rowland conversion for my Glock 21 Gen 4. In it I […]

    Pingback by Now, about those thunderbolts… « Ballistics by the inch | October 15, 2013 | Reply

  2. […] writes about his experiences with his Glock 21 converted to fire the .460 […]

    Pingback by .460 Rowland: Not an Elephant Gun, But Getting Close | State Of Tactical | October 15, 2013 | Reply

  3. I had the metal tab break on one of my magazines. The other one bent so I broke it and modified that area like you did.

    Next time your by a gun store check out the magazine for a 10 mm Glock, The metal tab on the magazine is bigger than on the 45.

    I did use the Glock contact form but have not heard back from them. I asked if the would consider making the Glock 21 magazine as strong as the Glock 20 and 29 magazine. People are now using 45 acp, 45 +P, 45 Super and 460 Rowland in the Glock 21 so it needs a stronger magazine.

    I have thought of spot welding a piece of spring steel to replace the broken metal tabs. But don’t have a source for a spot welder.

    Another thing I noticed was that after disassembly of the slide. When I tried by hand to feed a cartridge past the extractor it was rough and kind of binding. So I took the extractor out and polished it with sandpaper final grit 1200. A round now seems to feed by hand into that area a lot smoother with no binding. Will test it later this week.

    One caution; You might want to consider. The base (CUP) area of the Rowland cartridge is supposed to be stronger. You can see the difference when you compare 45acp and 460 Rowland.

    MY thought would be to trim the 460 Rowland case to 45ACP case size for any future testing on case size feeding issues instead of increasing the powder charge in a 45 case.


    Comment by Norman Neely | May 28, 2014 | Reply

    • Some good thoughts and feedback there, Norm. The tip on sandpapering the extractor is a good one – something that I’ll take a look at on mine.

      And yeah, I think that a beefier structure to the top of the mag is the thing. If Glock won’t make the change, perhaps an after-market supplier will offer them.

      Comment by James Downey | May 28, 2014 | Reply

      • Hi Jim:

        Just back from testing the polish job on the extractor. It made a world of difference. I had one failure (limp wrist?) to fully seat the slide, a slight hit with my hand fixed that. This was with Johnny’s Defense Against Large and Dangerous Game ammo. I only took 10 rounds the other 9 rounds fed just fine.

        10 round magazine of Johnny’s duty round 1 failure to feed jam. The rest fed fine.

        Two different 10 round loads of hand loaded rainier 230 grain plated round nose bullets they all fed fine.

        10 rounds of 45 super fed just fine.

        before my next visit to the range I will polish the extractor with a buffing compound to get it extra smooth. This should allow the magazine spring to feed rounds to that area even more smoothly than just the sandpaper polish job. But I am very happy with the sandpaper polish job and todays performance.

        The two other areas that need attention:

        1- A beefier magazine

        2- A 26 lb. recoil spring. Wolf Springs doesn’t have one.

        Wolfs website states that if the brass is ejecting farther than 8′ it indicates the need for a stronger spring. My brass on the Rowland ammo is ejecting in the 15 to 20 foot range. That’s with the extra strength recoil spring from Rowland and also with a wolf 24lb recoil spring.

        Jim your help in trying to locate a source for the above would be great.

        Todays shooting was using a magazine that had the metal tab broken out. I do have another magazine I will use next time I go to the range the metal tab on it is just starting to bend.

        I will also take a lot more 460 Rowland ammo with me, wished I had taken more today.

        I am going to order a box of:

        Cor-Bon Hunter Ammunition 460 Rowland 230 Grain Full Metal Jacket Box of 20

        It is a round nose so hopefully it will feed all right.


        Comment by Norman Neely | May 30, 2014

      • Good to get the additional range report, Norm. Glad to hear that the polish job worked so well!

        I’m going to tap into my network of contacts and see what I can scare up for a 26 pound recoil spring. If/when I find anything, I’ll post it here.

        And here’s a little something to raise goosebumps:

        Comment by James Downey | June 1, 2014

      • Goosebumps yes as both my reloads are with Unique. 7 grains and the other 8.5 grains of Unique. Won’t go any higher until after I get a Chronograph. The bullets are Rainier 230 grain plated round nose.

        Hope your contacts come through with a stronger recoil spring.

        I went back to the range yesterday and it did bend the metal tab quite a bit. No jams though shooting a box of Johnny’s Duty Rounds. So the buffing compound helped even more on polishing the extractor.

        I think a 26lb recoil spring or even higher as long as the slide can be racked by hand to chamber a round is needed.

        This might slow the slide down enough to keep from bending the metal tab.


        Comment by Norman Neely | June 1, 2014

  4. […] took my Glock 21 (5″ barrel) along for comparison, and shot over a single chronograph. Here are the average […]

    Pingback by First date with the Boberg XR45-S « Ballistics by the inch | January 2, 2015 | Reply

  5. […] The first version was with the Glock in the standard .45 ACP configuration, the second was with my .460 Rowland conversion kit in […]

    Pingback by Ammo test results in two versions of the Glock 21 « Ballistics by the inch | June 1, 2015 | Reply

  6. I know I am quite late to the game, but the mag damage problem sounds like it needs a heavier magazine spring to get the rounds UP faster. so the early slide return will not slam them into the mag tabs. That, along with heavier slide springs could do it. More Slide Mass could help also, think “Blow-Back” actions, like the dreaded “Hi Point” 😀

    Comment by underground12x8 | June 1, 2015 | Reply

    • Yeah, since that post I have come to the conclusion that slide speed is the biggest problem. I did swap out the standard mag springs for stronger ones, and that helped, but the real trick would be to either add slide weight or go to an even heavier recoil spring.

      Or just use .45 Super / .450 SMC loads … 😉

      Comment by James Downey | June 1, 2015 | Reply

      • Rowland offers that sight/weight combo part, and I have also dreamt of using T.I.G. welding electrodes as weight in strategic areas slides, and the grip cavity on a Glock for extra recoil taming. The electrodes are not too expensive, and I pick up the “stubs” when I work around pipefitters. Similar material is available online, google shopping. Tungsten s nearly twice as dense as lead…

        Comment by underground12x8 | June 1, 2015

  7. […] (overpressure) published load data. But that was done using .460 Rowland cases and shot through my converted Glock G21, which I knew could handle the extra power. When reloading, it pays to be careful and […]

    Pingback by Does primer size make a difference? « Ballistics by the inch | October 21, 2015 | Reply

  8. […] enjoy playing with the data. And please be sure to share it with others! Because while I have long been an advocate for the .460 Rowland — a cartridge I still like very much — I now think that the .45 […]

    Pingback by .45 Super data now published. « Ballistics by the inch | October 30, 2015 | Reply

  9. […] have written previously about converting a standard Glock 21 from .45 ACP over to .460 Rowland, and what is involved with that. Specifically, a new longer barrel with a fully-supported chamber […]

    Pingback by Dealing with power. « Ballistics by the inch | November 1, 2015 | Reply

  10. […] mags for my Glock 21, which I had upgraded to handle the .460 Rowland cartridge. The whole thing is discussed here, but basically what was happening was that the additional power/speed of the .460 Rowland was […]

    Pingback by Reprise: Clean Up Your Act — Get Rid of Your Dirty Magazines « Ballistics by the inch | August 20, 2017 | Reply

  11. […] to the .460 Rowland? Well, I could never get my G21 to stop chewing up mags when shooting full-power .460 Rowland out of it. And the recoil could be … daunting, even for […]

    Pingback by Reprise: Converting a Glock 21 to .460 Rowland « Ballistics by the inch | November 5, 2017 | Reply

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