10mm update 1


Last Monday I wrote about “Renewed interest in the 10mm Auto as an optimum defensive round“.  If you missed that article, you might want to read it before continuing with this one.

I haven’t been able to do any shooting this week, what with a winter storm moving through leaving a layer of ice beneath a layer of snow.  It’s made driving “interesting”, in the sense of the apocryphal Chinese curse.  My buddy Lawdog texted yesterday:

Karen in a Lexus just passed me going sideways.  From the expression on her face she’s going to require medical assistance to get that rich Corinthian leather out of her ***.

Don’t you love the professional law enforcement turn of phrase? 

However, I haven’t been idle.  I managed to trade a bunch of .44 Magnum ammunition that I had surplus to requirements for a bunch of 10mm Auto ammo that was surplus to someone else’s requirements, so I have plenty with which to test the Glocks.  I’ll look forward to that as soon as regular Texas temperatures return.

I also took the opportunity to consult with a couple of experts whose opinions I value.  They universally agreed with the initial post, that 10mm Auto offers a harder-hitting solution to defensive problems than 9mm or other less powerful cartridges.  However, both pointed out that .45 Super may be an equally good solution, equal to or even slightly more powerful than 10mm Auto.  In theory at least, it can be fired from any handgun chambered for .45 ACP, although components such as recoil springs may need to be upgraded.  It’s said to have even heavier recoil than a 10mm, but that’s anecdotal, so I’ll try it for myself and report my findings.  I’m going to put some through a Glock 21 pistol, the full-size twin to the 10mm Auto Glock 20.  (Of course, .45 Super ammo is even harder to find than 10mm Auto, but you can’t have everything!)  At any rate, if you already own a .45 ACP pistol that can handle .45 Super, this may be a simpler and cheaper solution than buying a 10mm, and equally effective.  Just a thought.

I have a tungsten recoil guide rod, more than twice as heavy as the factory Glock unit, fitted with a 23lb. recoil spring, 6lb. heavier than the factory standard 17lb. spring.  I’ll use it in both the Glock 20 and Glock 21, to test both 10mm Auto and .45 Super rounds, and see how much of a difference it makes.  I’m told it’s a major upgrade from a felt recoil perspective.  We’ll see.

Otherwise, research and preparations for practical testing continue.  Watch this space for more information as I get it.  Meanwhile, the winter weather continues – and I can personally testify to the truth of this observation:

Yes, that’s exactly what I was doing on Tuesday evening, in preparation for the winter storm’s arrival!  We went from 71 degrees (F) the day before to the lower 20’s the following day.  Oh, well . . . welcome to Texas!  I’ll get out to the shooting range as soon as I can wear more comfortable clothing again.



  1. Goodness honestly you really cannot conceal carry that 10mm can you?

    If I need something beyond a 45 ACP or a 9mm with good hollow points maybe I need a carbine?

    Drugged up felons and Antifa (but I repeat myself) often don't respond well to any sort of pistol therapy.

    I'm pretty sure a carbine will do the job, if I am doing open carry.

    So, I guess I am curious why you're going for a 10mm? You do have more experience than I do in this matter so it's a real interested query.

  2. You folks doing OK? Here in town (Wichita Falls), seems OK, but I'm mostly staying off the road lacking that trust in the other driver's abilities to handle the icy roads…

  3. It is clearing down here near Bandera TX. I spent Tuesday afternoon cutting down, cutting up and then splitting a dead oak tree for fire wood. It was a fine afternoon getting up into the 70's. Spent a pleasant Wednesday prepping for the storm in case there were electrical outages, since our electric coop sent out an email to that effect.

    It was cold for this far south. dWe have had uninterrupted electric service, so the generator wasn't needed. The fire has kept us warm in a more psychological way than a physical way.

    What is the difference between .40 S&W and 10mm? I have a Glock 23 that is just right for me to carry, concealed or open.

  4. @Michael: In terms of full-size pistols, if you can conceal a .45 pistol, you can conceal a 10mm. In terms of compact pistols, if you can conceal a Glock 19 (9mm) or 23 (.40 S&W), you can conceal a Glock 29 (10mm). It's not that hard.

    The reason I'm looking at 10mm is given in the initial article in this series – to deal with hopped-up felons who may not stop if/when hit with anything less powerful. At the moment, I'm not carrying a 10mm, but it's been recommended by street-wise cops that I consider it. I'm experimenting to learn more before I make a decision.

    1. You should carry the largest, and most powerful gun you can reasonably conceal, shoot, manipulate, and get follow ups with.

      That is going to be different for every one. Do I shoot my carry guns as well as my match guns? No, but I don't carry my match guns for the opposite reasons. Mobility v firepower. You are compromising something with any carry gun or caliber you pick .

      People get in arguments over perfect it best without regard to the person or their circumstances.

    2. Carried a Glock 29 for years. Not any more problem than a 19. 10 mm ammo for defense is best bought from "designer" manufacturers since they will load to the rounds potential. The big companies tend to load down a bit.

  5. If your looking at 45 super you might want to check out 450 smc (short magnum cartridge). It shares external dimensions with 45acp but uses a shortened .308 Winchester case which uses a magnum small rifle primer instead of large pistol. Leaves a lot more brass for a much stronger case than 45 super, and a ready supply of brass for a handloader. I think double tap sells 450 smc. They claim it should work in any +p rated 45acp, but you might want to upgrade the recoil spring.

  6. Peter,
    be aware that at some point 10mm was mostly downloaded powerwise, for various reasons. If your ammo is not original rated, you might as well not bother with using 10mm.

    If drugged up attackers became the norm, I would be inclined to look into getting a Desert Eagle in .50AE, if a concealed handgun was the limiting factor. That requires a shoulder rig, most likely. BTW, that was the fastest(by far!) major caliber handgun to bring the sights back on target that I ever encountered. (Much faster than an Officers Model 1911, or a 10mm Delta Elite.) Required a full Weaver, not a modified Weaver, to handle it. (I can't shoot Isosceles at all, due to support side wrist damage) For reference, 5'7", 120 lbs then.

    That DE was an indoor range rental, plus $1.00/round, when it first came out in the mid-90's. Didn't take long before they discovered that it was damaging their backstop! Those 300 and 325gr slugs hit hard at those speeds.

  7. Without wading into the caliber wars too deeply, one thought I had is that with recent decades conservation efforts combined with more people moving out of cities. It might be wise to also consider if your carry piece is "enough gun" for potential non-human threats in your neck of the woods.

  8. A middle-ground on the 40 S&W vs 10mm debate is that you can get about 200 more fps over factory ammo if you reload or of you know a trustworthy reloader.

    Factory ammo uses non-canister grade powders and they dial-in for every bulk delivery. That means that the advertised velocity must be achievable with the very fastest powder they are likely to encounter.

    Reloaders do not have a lab to dial in the pressure and velocity. Therefore "cannister" powders are much, much more uniform than the bulk powders delivered to factories that produce ammo.

    For example, the Hodgdon reloading site lists 150 grain Nosler hollowpoint in front of 9.2 grains of the powder "Longshot" as capable of 1320 fps at the muzzle.

  9. Heck, just figure out how to carry a 9 – as in "long 9 pounder" 😁 if you can launch a bowling ball accurately and fast enough, then the caliber junkies will debate the power vs. Concealability of ten-pin over Duck-pin balls. What rifling twist for duck-pin? Elmer Keith concealed his 4".44 Smith by sticking it in his cowboy boot-top, when in DC during the '68 riots, or going IWB with his single-actions, letting the gun hang on the open loading gate when riding a train in Canada when private carry was verboten. He was recognized as a well-known handgun hunter, and some early Karen thought it sporting to brace him if he was packing. He saw them coming, however so he closed the loading gate and let the gun slip down his trouser leg into his bloused boot-top (clothes being much looser in the '50s) so when asked, he simply opened his coat and showed them his empty belt! (Good thing they didnt check his luggage for spare ammo!)
    This is all in his autobiography, "Hell, I was THERE!", makes for fun reading…
    Being (unfortunately!) Of a girth that I can do that w/my 7 1/2" Super Blackhawk, concealing isn't an issue, but I doubt you'll reach the 10 MMa's full potential in commercial ammo, without reloading it. Buffalo Bore may prove me wrong, of course, they do seem to know the VooDoo of wringing max performance out of various munitions…. waiting with interest to see your results.

  10. My daily carry is a Glock G20. The main reason is because it holds 15 rounds in the magazine. Prior to the G20 I carried a G37 45GAP. The 45GAP is roughly equivalent to 45 ACP+P. The biggest drawback is that it only holds 10 rounds in its magazine. The 45GAP was popular with many local and state law enforcement agencies until ammo got impossible to find in the Obama years and they switched over to 9mm. The 45GAP has become a boutique round.

    I have friends that work at Glock in Smyrna. We all reload our ammo. Their view is the Gen3 45GAP is a better platform for the round as it can handle powder charges well beyond recommended max loads. One in particular has a Gen3 45GAP G38 with over 50k rounds through it that almost all of it is at 10mm velocities or faster. The interesting thing about all of them is they all have a G27 in 40 S&W as their carry gun.

  11. And how IS Mr. Lawdog, Peter? Still hunting for the Muse who left town after rolling a rich drunk,or personal affairs still tying him up? Hoping he is doing well? Miss those zingers of his, as well as the stories! Mainly, wish him well from his readers, we miss him!

  12. If shot placement trumps caliber size, as most tactical trainers believe, wouldn't you be better off learning to put a couple 9 mil in the same spot in rapid succession. Less recoil, regain site pic faster, etc.

    I'm big enough to conceal just about anything. Monday through Friday I wear a G19. Saturday and Sunday usually a Commander. Why? Because I work for living and wearing a large framed gun while I'm working is a pain in the ass. I forget the G19 is there.

  13. @B_Rad: The shot placement issue, particularly with fast-moving hopped-up targets, was addressed in the first article in this series (linked above). With vanishingly few exceptions, shooters are much less accurate in actual combat than they are on the square range where nobody's shooting back at them.

  14. @B_Rad: Yes, but I remain unconvinced. Seems to me more like a Natural Point of Miss, when one considers the outcome of so many gunfights. That's why we need sights.

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