Ballistics by the inch

Dealing with power.

About 40 years ago, when I was an idiot teenager (yeah, I know — redundant, particularly in my case), we got this ’48 Willys Jeep. Since the engine was shot, we dropped an Olds V-6 in it. This was, essentially, like strapping a rocket to a skateboard. And it was too much power for idiot teenage me to handle.  Twice I snapped the driveshaft on the thing, just dumping the clutch too damned quickly. Twice. My uncle (who I lived with) was certain that I had been racing or something similar. The truth was, I didn’t even have that much of an excuse; I had simply goosed the engine too much and popped it into gear too fast. The original driveshaft just couldn’t handle that much of a power spike.

This is kinda what happens to your poor .45 ACP firearm when you decide to run some .45 Super through it.

With the Jeep, we wound up putting a more robust driveshaft in it. And I learned that if I wanted to keep driving it, I needed to be less of an idiot.

This analogy holds to how you should approach handling .45 Super power out of your .45 ACP gun. Chances are, very occasional use of these much more powerful loads won’t cause any problem in a quality, modern-made firearm. But if you’re smart, you’ll either greatly limit how many times you subject your gun (and your body) to that amount of power, or you will take steps to help manage it better and extend the life of your gun.

Typical ‘standard’ (non +P) .45 ACP loads tend to have a maximum pressure of between say 15,000 PSI and about 18,000 PSI. When you get past that, you get into ‘over-pressure’, or +P territory, up to about 23,000 PSI. This is the range most common modern firearms are built to handle safely.

But .45 Super generates more chamber pressure than that. How much more? Well, it’s a bit difficult to say, since there is a surprising dearth of data readily available. Neither my 49th Edition of Lyman’s Reloading Handbook nor my 13th Edition of Cartridges of the World have data for the .45 Super. Real Guns has some reloading formulas for .45 Super which give results consistent with our tests, but there are no pressure specs listed. Hodgdon Reloading has some pressure specs (in C.U.P.), but all their listed results for .45 Super are well below what our tests results were. Wikipedia lists .45 Super as having a maximum pressure of 28,000 PSI, and given that .460 Rowland is usually considered to run 35,000 – 40,000 PSI, that is probably in the correct ballpark.

I 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 which accommodates the longer case of the .460 Rowland, a 23 pound recoil spring, and a nice compensator to help tame the recoil. I also changed out the magazine springs, using an aftermarket product which increases the spring power by about 10%. This is because even with the other changes, the slide still moves much faster than with .45 ACP loads, and the increased mag spring power helps with reliability in feeding ammo. But even with all of that, shooting full-power .460 Rowland loads tends to cause damage to my magazines (as seen in the linked post).

Do you need to do all that in order for your firearm to handle frequent use of .45 Super loads? Well, I think that if you want to use a .460 Rowland conversion kit, it *will* tame the amount of recoil more than enough, but I don’t think that it is necessary to go quite that far. I should note that I have now run several hundred .45 Super loads through my Glock 21, and the gun has operated flawlessly — WITHOUT any damage to the magazines.

Converted G21 on left, G30S on right.

Converted G21 on left, G30S on right.

Rather, I think that the smart thing to do is to start off with going to a heavier recoil spring, perhaps swapping out a metal guide rod for a plastic one (if your gun comes with a plastic guide rod). Stronger magazine springs are probably still a good idea, to aid with reliable feeding. If suitable for your gun, add in a recoil buffer. These are the steps I have taken with my Glock 30S, and am planning for my Beretta Cx4 Storm. So far I have put a couple hundred .45 Super loads through the G30S with this configuration, and it has operated without a problem — again without any damage to the magazines.

As I said in my previous blog post, I still think that the .460 Rowland is a hell of a cartridge. But I think that the .45 Super offers almost as many advantages to the average shooter, with less hassle. I would still recommend that anyone who intends on shooting more than the very occasional .45 Super loads out of their gun consider making some simple changes to handle the additional power and extend the life of their gun. Don’t be like the idiot teenage me; deal with the power intelligently.


Jim Downey



November 1, 2015 - Posted by | .45 ACP, .45 Super, .450 SMC, .460 Rowland, Data, Discussion., Links | , , , , , , , , , , , , , , , , , , , , ,


  1. Good Analogy, Jim!
    I built engine combos for quite a while, and ALWAYS cautioned my people to be ready
    to bolster nearly everything else associated with the drive line. While doing the V6 Mustang
    EFI setups, it was usually good-to-go because the Moose always had (in most later model years)
    V8 transmissions, radiators and even the rear ends were found in some prior V8 cars.

    Be ready to change a LOT of parts, when you go doubling the pressure specs of the cartridge!
    (for the peanut gallery) 😀

    Comment by underground12x8 | November 4, 2015 | Reply

    • Heh – true enough. Though I think that it is somewhat easier with firearms … at least the parts don’t weigh as much! 🙂

      Comment by James Downey | November 5, 2015 | Reply

  2. […] I want one which is also going to have a fair amount of velocity behind it (which is why I have adapted my .45s to handle the .45 Super). All things being equal (sectional density, bullet configuration and composition), velocity is […]

    Pingback by Velocity is great, but mass penetrates. « Ballistics by the inch | November 8, 2015 | Reply

  3. […] while you want to take steps to manage the power of a round like the .45 Super on the INSIDE of your firearm, you also have to take steps to manage […]

    Pingback by Dealing with power, part II: Recoil. « Ballistics by the inch | December 23, 2015 | Reply

  4. […] love my Cx4 Storm carbine, as I have mentioned and reviewed. Particularly once it was set-up to deal with the additional power of the .45 Super cartridge, it has proven to be a reliable and […]

    Pingback by Working within your limitations. « Ballistics by the inch | October 16, 2016 | Reply

  5. […] I have previously noted, I have now changed over to using the .45 Super cartridge rather than the .460 Rowland because the […]

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  6. […] I have previously noted, I have now changed over to using the .45 Super cartridge rather than the .460 Rowland because the […]

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

  7. Jim,

    I wonder if you could add any recent updates to your usage of 45Super through your Glock 30S? I Have recently purchased a G30S, and have considered putting in an after market (longer and threaded) barrel to maximize the velocity for hunting/backwoods use. I am thinking about adding a lightweight compensator (nothing as huge as the 460R comp) and a stiffer spring. With a fully supported barrel, like from barsto or kkm, would you expect I would have any issue shooting hot 45 Super? Anything I should consider with this approach?


    Comment by Bob | November 26, 2018 | Reply

    • Hey Bob, thanks for your comment.

      Since I wrote this piece three years ago I’ve shot and carried the G30S a lot with the minor tweaks mentioned: heavier recoil spring (23 pound) and stronger mag spring (the Wolff +10% ones). It made a substantial difference in felt recoil, and has helped handle the extra power. Since then, I’m sure I’ve put 1,000+ .45 Super power rounds through it (mostly my own reloads). My gun shows no signs of excessive wear that I have been able to tell.

      Adding a longer barrel and/or comp would of course help, but I don’t have any experience with that on the G30S.

      Comment by James Downey | November 26, 2018 | Reply

      • Jim, thanks for your quick response! If you have a sec, I have a few more detailed questions.

        How hot of 45 Super ammo are you running through your G30S? Have you used something equivalent to the Underwood or Buffalo bore loads? or are we talking even more? (How “hot” are your handloads??)

        Also, have you ever shot 45 super out of your 30S over a chronograph? Any idea what kind of velocity you are getting compared to regular 45 + P?

        So, as the 30S has a slimmer/lighter barrel and slide than a regular G30 (or G30SF)… is there level (or hotness) of 45 Super that you would choose to not put through your pistol with the stock barrel setup (If I have understood you correctly, you have the stock barrel)? Have you experienced any case bulging from the less supported stock barrel? Is there a point in your opinion at which the better supported case structure of an after market barrel would come into play?

        Have you ever had a chance to shoot 45 super through a regular G30 and your G30S side by side? Is there a noticeable recoil difference with the heavier slide of the regular G30, or can that all be mitigated with the heavier spring?

        Thanks again!

        Comment by Bob | November 26, 2018

      • My reloads are a little under the power of the BB or Underwood stuff, just to save on some abuse to my hands. I almost always finish off with a mag or two of factory loads, though.

        Looking back over my reload notes, I initially worked up loads to match the BB specs in our .45 Super data, then backed off just a bit. What I typically shoot now gets about 1140fps for a 185gr, 1100 for 200gr, and 1040 for 240gr. Now, that’s just using a single chrono, and I’m not being nearly as careful as when we do formal tests, but those are the right ballpark. Those are all out of my G30S, the numbers for my G21 and my Beretta Cx4 are higher, of course.

        Also, I am using Lone Wolf replacement barrels in both Glocks, so those are fully supported. As I recall, I swapped out the G30S shortly after getting it. Before that, I had run into some problems with hot .45 Super out of the G21 with a stock barrel causing bulging. No problem with the .460 Rowland barrel, but I decided to go to a .45 Lone Wolf in it as well, so the .45 Super would properly headspace on it. Personally, I’d switch to the supported barrel, just to be safe.

        I haven’t done a comparison between the G30 and the G30S. The G36 we used for our tests was stock, and I recall it being ‘stout’ to shoot.

        Hope that helps.

        Comment by James Downey | November 26, 2018

      • Jim,

        Thanks again for all the info! very helpful! You have made me reconsider whether I need to go to the extra expense of finding a threaded/longer barrel, rather than just sticking with a stock length… it sounds like the velocity you are getting out of your set up is giving energy returns similar to the g29. (Although, I would be curious about what kind of per-inch velocity increase I would possibly see going to a 4.6, or a 5.6 inch barrel?)

        Also, are you able to shoot normal 45ACP or +P with that heavy spring? Or do you need to swap back to a lighter spring for plinking? I see a 23lb spring setup on Lone Wolf’s site… but it says its for a G30 (sorry for my ignorance, but will the double spring setup for G30 also work for G30S/36?) “Wolff Extra Power 23lb Guide Rod and Spring for G30 WOL-50923”


        Comment by Bob | November 26, 2018

      • I checked the spring packaging (where I have the original assembly), and it says for the G29, 30, and 36. So evidently they’re all the same. It’s been long enough that I don’t remember how I made that determination, but it seems correct.

        And yeah, you can’t cheat in physics — with the 23lb assembly in place, anything under a .45 +P won’t cycle properly. I usually just shoot loads at that power, but if I want to step down it’s easy enough to swap out the springs.

        Just compare our data to see what an extra inch or two will gain down at the short barrel length. That should get you in the ballpark. The only way to know for sure is to chrono your gun & ammo.

        Comment by James Downey | November 26, 2018

  8. […] 9mm Timberwolf, and that reminded me to look into getting one for my G21 I have set up to handle .45 Super. This […]

    Pingback by Customized Timberwolf G21 « Ballistics by the inch | December 11, 2020 | Reply

  9. […] 9mm Timberwolf, and that reminded me to look into getting one for my G21 I have set up to handle .45 Super. This […]

    Pingback by Customized Timberwolf G21 | Communion Of Dreams | December 11, 2020 | Reply

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