[darkwriter77]

Thinking of trading in my Gen3 Glock 21 w/10mm conversion barrel on a Gen4 G20 or G40 (or a Gen3 G20SF, if I can find one) - should I? Or shouldn't I?

Kinda came to the conclusion that my fingers are just a tad short for the regular ol' Gen3 G20/G21 frame, although the Gen3 G19 and G26 fit me just dandy (as well as a plastic 2x4 can fit one's hand, anyway ), and I've come to love the 10mm more than the .45 ACP out of that particular platform, plus it would seem to be a bit more practical in the to-and-from-work open-carried role the G21 has been serving for me. (Two extra rounds, and slightly better barrier penetration.) I don't trust the conversion barrel enough for carry, as it's been kinda ammo-picky, but it shoots every bit as nicely as the original .45 ACP setup, sooooo ... yeah. Still have my 1911, XDS45 4.0", Governor, and Tanfoglio Witness to satisfy my various .45 ACP itches.

Any thoughts? Suggestions? Go with the Gen4 G20? Or G40? Or maybe hold out for finding a Gen3 G20SF?

 

[haertig]

I've never shot a 10mm. Don't they kick like a mule? I've always considered 10mm to be impractical for self defense, much like .44mag. Overpowered, and just too difficult to practice enough to learn how to control the recoil, if you ever can. I don't have trouble controlling .44mag ... for the initial shot. Followup shots would be all over the place, unless you allowed me several seconds to regain my wits. I'd expect the 10mm to be similar.

 

[H2OMAN]

Have you handled a SF yet?

I have a 20 and two 21s, but I've never handled a slim frame.

 

[BlakeHanson]

I've never shot a 10mm. Don't they kick like a mule? I've always considered 10mm to be impractical for self defense, much like .44mag. Overpowered, and just too difficult to practice enough to learn how to control the recoil, if you ever can. I don't have trouble controlling .44mag ... for the initial shot. Followup shots would be all over the place, unless you allowed me several seconds to regain my wits. I'd expect the 10mm to be similar.

I always wondered why KT didn't offer the Sub2000 in 10mm. Shooting the sub with 9mm is like a pellet gun. The carbine could tame down the 10mm viscous recoil and at the same time become a powerful weapon for one that shoots just a :quoteistol:quote: cartridge.:headstratch:
It would be a perfect match:rayof:.

 

[jonnin]

I've never shot a 10mm. Don't they kick like a mule? I've always considered 10mm to be impractical for self defense, much like .44mag. Overpowered, and just too difficult to practice enough to learn how to control the recoil, if you ever can. I don't have trouble controlling .44mag ... for the initial shot. Followup shots would be all over the place, unless you allowed me several seconds to regain my wits. I'd expect the 10mm to be similar.

10mm is somewhere between a 357 and a 44 mag depending on the load data and barrel lengths being used. Its typically 3/4 of the way between the 2.

In a semi auto, the recoil is lessened significantly; I can shoot mid-tier practice 44 mag 1 handed in my desert eagle, which weighs 3 pounds empty and has the mother of all recoil springs and a type of gas piston. I can shoot that one rapidly in a 2 handed defense stance better and faster than I can shoot a kel tec 9mm (for various reasons). In a lightweight glock 10mm will kick bad enough; most shooters could not handle this (its why the caliber effectively died, the recoil was too much for the feds that wanted it in the first place). If you want a 10mm, get a 1911 version, youll thank me.

agreed on the rifle too. Ive shot a couple of 44 mag rifles and they are EXCELLENT. Mild recoil and superior ballistics (more fps).

I really, really, really like shooting my big 44. Its just FUN. Its not something I would carry, being gigantic and heavy. Its a toy or maybe a hunting pistol. I would be better off with my PLR 16 and only slightly more inconvenienced carrying the 223.

 

[6-b-kwik]

I love mine have a 20 and 29.they both are wearing 9x25 Dillion barrels. U think 10mm flys shoot 9x25. Underwood ammo has really good hot ammo that's fun to shoot.i carry my 29 daily and practice enough with it I feel comfortable.the only downside is I don't reload and it gets costly.i choose Glock because they can handle hot loads if your going to shoot off the shelf 10mm I would just buy a 40 and be done. My preference the store stuff didn't have enough snap for me.good luck on your search

 

[6-b-kwik]

Both of my 10mm

 

[H2OMAN]

Nice!

My 20 has the standard barrel plus a 6" Glock 'Hunter' barrel.

 

[CJP32]

I've been seriously considering a gen 4 Glock 40 as my next pistol so you can guess my answer. It's nothing I need but I find the 10mm interesting especially when looking at underwood ammo.

 

[CJP32]

I always wondered why KT didn't offer the Sub2000 in 10mm. Shooting the sub with 9mm is like a pellet gun. The carbine could tame down the 10mm viscous recoil and at the same time become a powerful weapon for one that shoots just a :quoteistol:quote: cartridge.:headstratch:
It would be a perfect match:rayof:.

The current, blow back design can't handle more recoil than the 40. There was some talk of a 357sig conversion that would require a tungsten bolt but I don't think it ever left the drawing board. A 10mm sub2000 would be great but it will never happen.

 

[ral357]

The current, blow back design can't handle more recoil than the 40. There was some talk of a 357sig conversion that would require a tungsten bolt but I don't think it ever left the drawing board. A 10mm sub2000 would be great but it will never happen.

Rumor has it that a few 357 sig units were made but it's just too much for the design to handle.....

http://www.thektog.org/forum/f85/how-about-making-264888/

 

[Beastly]

I'm not sure it is practical, but I sure like the idea.

Recoil control, even at speed, is a learnable skill.

 

[darkwriter77]

I've never shot a 10mm. Don't they kick like a mule? I've always considered 10mm to be impractical for self defense, much like .44mag. Overpowered, and just too difficult to practice enough to learn how to control the recoil, if you ever can. I don't have trouble controlling .44mag ... for the initial shot. Followup shots would be all over the place, unless you allowed me several seconds to regain my wits. I'd expect the 10mm to be similar.

Negative. Recoil with the 10mm loads I've tried with the conversion barrel in my G21 has been no worse than .45 ACP through the same. Part of that may be due to the aforementioned "meh" loads (although the Winchester Silvertips I ran through it were pretty hot), but most I would attribute to the size/build of the G20/G21 frame and the aftermarket 22# spring that I'm using with it (instead of the 17# factory spring). The recoil impulse is faster, but not heavier, and the report is louder but nothing anywhere near as loud as a .357 Magnum or .22 TCM. And in terms of ballistics, the 10mm is not "overpowered" in terms of penetration, as long as you're not running hard cast lead, FMJ's, or Lehigh Extreme Penetrators for defense against humans. (If defending against bears and other woodland predators, though, that would be a good thing.) Winchester Silvertips and loads using the Barnes copper bullet or Gold Dot bullet have all performed quite nicely in testing - over 12", but under 18", with lots of expansion.

Have you handled a SF yet?

I have a 20 and two 21s, but I've never handled a slim frame.

Prior to the basic Gen3 G21 that I currently have, I once had a G21SF. Still kicking myself in the butt for getting rid of it. I've compared 'em side-by-side at the LGS a couple of times, and the difference in feel is significant. The SF frame feels more like the G19 to my hand, whereas the plain G20/G21 frame feels like ... well...

I'm not sure it is practical, but I sure like the idea.

Recoil control, even at speed, is a learnable skill.

Why wouldn't it be practical? This isn't a .50 AE Desert Eagle (or even a .50 GI conversion). I've fired the 10mm-converted G21 one-handed, both right and left. It never flew out of my hand or whacked me in the head or anything wild like that; rather, it recoiled much like .45 ACP, although it was more of a "bump" rather than a "push." Actually, follow-up shots with 10mm were a tad quicker for me than with .45 ACP.

I haven't tried 10mm out of anything else yet because the other platforms I've looked at (the 10mm 1911 and Tanfoglio Witness conversion) seem to be problematic at best in terms of reliability, so I can't attest to whether the G20/G21 platform is the easiest-recoiling setup available. But I do know that mine feels quite acceptable overall. I'm just not convinced of the reliability of the conversion barrel that I have, at least not enough to trust it for carry, plus the whole "he used a highly customized super death ray gun!" factor of a caliber-swapped carry gun (I'd prefer a factory-chambered 10mm to minimize the lawyer bait).


FWIW, Mechtech does make a carbine conversion for the G20/G21 in 10mm. Seems neat, but I don't really have much use or desire for a pistol-caliber semi-auto carbine.

 

[BlakeHanson]

The current, blow back design can't handle more recoil than the 40. There was some talk of a 357sig conversion that would require a tungsten bolt but I don't think it ever left the drawing board. A 10mm sub2000 would be great but it will never happen.

Let's just say "theoretically" that KT made a beefed-up S2000 in 10mm with a 16" barrel.
Let's look at the energy numbers and how it would stack up with other rounds with a 16" barrel using typical ammo:

9mm- 400-550 ft-lbs.
.45 ACP- 450-600 ft-lbs.
.40S&W- 500-700 ft-lbs.
10mm- 600-850 ft-lbs.

For reference: a .44 mag with 5" barrel- 600-825 ft-lbs.

I think it would be worth the effort.
The 10mm could possibly come back from obscurity.
It is too powerful to control in a pistol but would make a potent carbine round. Due to the carbine's length, muzzle-flip would not be a big problem and follow-up shots would not be in the clouds.

 

[darkwriter77]

One thing I failed to consider is the versatility of being able to swap calibers (just for giggles, if nothing else) on a given platform. With the G21, I can run .45 ACP as well as conversions for 10mm, .40 S&W, .357 Sig (yawn), and supposedly 9mm (although I'm not sure HOW, regarding the mags). If I go with the G20 or G40, then .45 ACP is off the list. And with the G40, there are almost ZERO conversion barrels available in that length from what I've seen (just a .40 S&W barrel by Lone Wolf), so it would be 10mm-only. Again, not that I don't have other .45 ACP options on hand, but I like versatility, especially if a time comes that I need to whittle down my collection and find it necessary for each gun to fill more roles. The ridiculously long sight radius and slimmer slide of the G40 is appealing, but the G20 gives more options (and the G21SF more options still, although conversion barrels aren't ideal for carry purposes).

The obvious solution here would be to just buy one of each, but alas, I have not won the lottery yet ... and I'm not sure how many years it's been since I even bought a ticket...

 

[CJP32]

Blake, I've seen some 10mm that's in 700ft lb range out of a pistol, a 130g jhp moving at 1600'/Sec. I can only imagine what it would be doing out of a 16" barrel, the bullet might come apart or something.

 

[darkwriter77]

Blake, I've seen some 10mm that's in 700ft lb range out of a pistol, a 130g jhp moving at 1600'/Sec. I can only imagine what it would be doing out of a 16" barrel, the bullet might come apart or something.

With something like that, I'd say JHP's are pretty much out of the equation, and soft points would be more practical, as they're not as apt to flatten out as quickly. But that's something more desirable for hunting applications, and anyway, it's not really what I'm looking into at the moment.

Can't really order anything today or tomorrow because the distributor of my LGS is closed on weekends, so I dunno if they can even get hold of anything right now. They did have a G41, G34, G35, and of course a G17 for me to compare side-by-side. All have almost the same identical grip frame dimensions (at least according to my uncalibrated eyeballs and hands), and all except for of course the G17 were almost identical in overall length and even slide width. Compared the G41 to both a Gen3 G21 and G21SF, and ... wow. Not only is the grip obviously more comfortable than the plain Gen3 G21, but the slide on both G21's was freaking FAT by comparison, WAY thicker, and made it feel even more top-heavy than the G41 with its 6.2" barrel. And being that the G40 and G41 are pretty much clones aside from caliber, welllllllll ... yeah.

Placed a sorta pre-order and traded in something I fell outta love with: 686+ 2.5" ... still keeping my 4" model, but the 2.5" never gets taken out of the safe for carry over the Ruger SP101 2.25". Gonna find out Monday if they can get the non-MOS G40, since I have no need or want for a red dot sight on a carry pistol (I don't even like them on range-only pistols), and place the actual order then.

 

[Beastly]

Blake, I've seen some 10mm that's in 700ft lb range out of a pistol, a 130g jhp moving at 1600'/Sec. I can only imagine what it would be doing out of a 16" barrel, the bullet might come apart or something.

XTP's reportedly perform well at higher speeds.

 

[BlakeHanson]

Blake, I've seen some 10mm that's in 700ft lb range out of a pistol, a 130g jhp moving at 1600'/Sec. I can only imagine what it would be doing out of a 16" barrel, the bullet might come apart or something.

BBTI didn't test anything lighter than the 135 grain.
The velocity difference between an 11" barrel up to a 16" barrel are pretty much flat so it's unlikely to come apart. The only gain there is to get it out past the SBR stamp.
The big gain is to be had when it is moved from a typical 4"-6" pistol barrel that the round is usually fired out of, out to 11+ inches. Gains in FPS of 150-200+ FPS are typical with the same load and the corresponding increase in ft-lbs.
Putting that kind of power in a carbine that folds into a 16" package would be a game-changer. It would shoot farther, flatter, and with greater energy than anything else like it.

 

[buzzsaw]

I would expect the 10 mm to work better than the .357 SIG in a SUB 2000-type blowback action carbine since it has a straight-walled case. Bottleneck cases don't work well with blowback actions since the cases get their heads ripped off, or fail to maintain a seal as they are extracted while still under pressure. I suspect that Kel Tec's .357 SIG prototypes with the tungsten bolts required a very narrow range of ammunition parameters to function reliably. Releasing such a product to the general public would be a technical support nightmare.

A 10 mm SUB 2000 would probably need to be a bit beefier or have a metal receiver, like the SUB 9's of old.

buzzsaw