Some 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 mentioned how much I like the resultant gun, but also how I was having some problems with magazine wear when shooting full-force .460 loads.
Well, after thinking a lot more about it, as well as discussing it with people online and with the other BBTI members when they were here for the recent tests (one of whom has been a Glock armorer for 15+ years) a couple different strategies emerged for me to test. Briefly, those were:
- See whether putting in a heavier mag spring would help
- See whether the problem was due to the case length of the .460 Rowland cartridges (they’re 1/16″ longer than .45 ACP).
- See whether the problem was due to the *power* of the cartridges rather than the length of the cases.
To test the first, it was a simple matter to get a more powerful mag spring and test it in one of the magazines. I picked up a Wolff magazine spring from Midway and did so.
To test whether it was the simple case length of the .460 Rowland cases, I made up some .460 Rowland rounds using .45 ACP reloading standards.
To test whether it was the *power* of the .460 loads but not the case length was another matter. Here’s where we get to the Don’t Try This At Home part of today’s blog post: I made up a number of .45 ACP rounds which were loaded to .460 Rowland specs.
Let me repeat that again: Don’t Try This At Home. These are wildcat rounds, and potentially dangerous. Shooting them in a gun not rated for .460 Rowland stresses could very well result in catastrophic failure of your gun, of the “KABOOM!” variety. Even shooting them in a gun designed to handle .460 Rowland power was risky, since the .45 ACP cases do not have the same strength as the .460 Rowland cases. I made up just 10 rounds of each of these loadings, and was careful to make sure I shot them all, so that they didn’t accidentally wind up in a .45 not strong enough to take the punishment.
Here are each of the loadings I made up, just for reference, along with their approximate chrono results:
- 185gr XTP bullet, .45 ACP case, .460 Rowland power 1480fps
- 200gr RNFP bullet, .45 ACP case, .460 Rowland power 1440fps
- 230gr RNFP bullet, .45 ACP case, .460 Rowland power 1350fps
- 250gr LFN bullet, .45 ACP case, .460 Rowland power 1250fps
- 230gr RNFP bullet, .45 ACP case, .45 ACP power 920fps
- 230gr RNFP bullet, .460 Rowland case, .45 ACP power 925fps
- 185gr XTP bullet, .460 Rowland case, .460 Rowland power 1490fps
- 200gr RNFP bullet, .460 Rowland case, .460 Rowland power 1420fps
- 230gr RNFP bullet, .460 Rowland case, .460 Rowland power 1355fps
- 250gr LFN bullet, .460 Rowland case, .460 Rowland power 1265fps
No, I’m not going to give the specific powder amounts for any of those. I used Hodgdon Longshot powder, and you can look up the specs if you want to know more.
In addition, I had these factory loads on hand for comparison, along with their approximate chrono results:
11. 185gr DPX .45 ACP +P 1110fps
12. 230gr GDHP .45 ACP 850fps
13. 230gr JHP .45 ACP +P1040fps
14. 230gr JHP .460 Rowland 1380fps
15. 255gr LFN .460 Rowland1260fps
OK, a couple of comments before I go further: those are “approximate” chrono readings because I wasn’t being anywhere near as careful as we are when we do formal BBTI testing. To wit: I was just using one chrono; I wasn’t worried about getting the exact same number of readings (so long as I got three or four, I wasn’t too worried about it); and I didn’t do anything to control for consistent lighting or suchlike. But they should all be in the right ballpark.
So, looking over all those, you will see what I see: that there was a remarkable consistency in power levels, whether you’re looking at my reloads or factory loads, and between those rounds which used either .45 ACP cases or .460 Rowland cases. That tells me that following the published data for .460 Rowland reloads, and making some intelligent decisions on how to adapt those to the .45 ACP cases for purposes of this experiment, was by and large successful. Meaning that I can use those loads to fairly evaluate what makes a difference on the basic problem I was investigating: what is causing the magazine damage and how to resolve it.
So, what conclusions did I draw from all this?
First, the more powerful magazine spring seemed to help with consistent loading. I will be swapping out all the Glock 21 mag springs I have. This makes intuitive sense, since the slide is moving faster when shooting the more powerful rounds.
That doing a little customizing on the magazines also seems to help a great deal. Here’s a pic showing an unaltered magazine and one I have taken a Dremel tool to:
Note that these are just the magazine ‘boxes’ — the guts (spring, follower, etc) have all been removed for clarity.
With the altered magazine and stronger spring, any problems I had with Failure To Feed was minimized.
And most important, it is the *power* of the round, not the case length, which seems to cause damage to the unaltered magazines. Shooting the .460 Rowland power loads in the .45 ACP cases demonstrated this. Conversely, shooting the .45 ACP power loads in the .460 Rowland cases didn’t cause any magazine damage at all.
Two additional notes I want to add: the first is that I had pretty consistent problems with the heavy Lead Flat Nose rounds in all configurations. They kept getting jammed up in transitioning from the magazine into the chamber. I’ll probably continue to experiment with this in the future, but I’m not too worried about it, since many guns run into some ammo specific problems.
The second is that once again I was really impressed at just how well this reconfigured Glock 21 did with .45 ACP loads. Seriously, with the .460 Rowland conversion in place, there was very minimal recoil (more than a .22, but not much) and it was VERY easy to control and shoot the gun well. I suspect that going forward the vast majority of the shooting I will do with this will be using standard .45 ACP reloads, saving the much more powerful .460 Rowland rounds for occasional practice. In this sense, I am thinking of the .45/.460 relationship the way I think about .38/.357 — it seems to be a perfectly appropriate analogy.
Now that I have all this sorted, I can go ahead and write up a formal review. But I thought I would share a little of the process of how I got to this point.
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:
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:
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:
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:
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.
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