G40 10mm/.40S&W

[oink]

Kinda a repost from the "New Toys" thread:

I ordered a .40 barrel (KKM Precision) for my G40. Well see if it pays for itself in reduced ammo costs. Also see if it's reliable enough do be used for defensive purposes. As far as I've been able to tell nobody makes good defensive 10mm loads that are appreciably better or even as good as cheaper more easily available .40 loads. Hunting loads are a different story.

I'd gladly go full power if I could find what I wanted. I'd like a FULL POWER round that only penetrates about 12" but that expands dramatically to about an inch in that distance. Ypu'd think if they can get a lumbering 45ACP to 1" they could get a faster heavier 10mm to do it.

According to Lucky Gunner the .40 S&W Barnes 140 Grain TAC-XPD HP comes the closest doing around something over 1000FPS penetrating 12" and expanding to .76". This out of a 3.42" G27. Don't need a 10mm for that. Hopefully with the mild resurgence of the 10mm some good load development by major manufacturers will result.

Well after getting the new barrel I decided to do some playing with what I had on hand. I won't really call it testing. First of all it seems to shoot just fine with the ammo that is generally my least favorite, Blazer aluminum. It seems to function just fine with those. No issues at all other than it only throws the brass a foot or two. But it throws them as far as my Glock 10mm barrel throws PPU 10mm hardball or JHP, pretty mild stuff.

So I did a little chronograph playing with both barrels:

10mm
Sig V Crown 180gr JHP - 1219fps
Sellier & Bellot 180gr FMJ - 1125fps
PPU 170gr FMJ - 1089fps
PPU 180gr JHP - 1016fps
I had some Sig hardball but if I have any left I can't find it. It seemed, IIRC, to be hotter than their JHP.

.40 S&W
Barnes TAC-XPD 140gr HP - 1145fps
Blazer Alu 180gr FMJ - 1098fps
PPU 180gr FMJ - 1004fps

So, I'm left with the Sig 10mm which if it works, it works great but is susceptible to pretty bad over penetration, which I very much don't want. Or the 40 Barnes 40 that I'm pushing a little faster with the 6" barrel so there's some unknown with that but which otherwise seems to perform well but isn't taking full advantage of 10mm potential.

The KKM barrel seems to work great. I like it. It would probably be best with a lighter spring but it throws the 40s as far as it throws the PPU 10s.

I think I'd like a 10mm barrel too and a barrel for my G23 and G21 (both Gen 2) so I can shoot lead out of them. Truth be told the G21 has had plenty of lead through the OEM Glock barrel already. I'd kinda like one for my G19 but I'll worry about that when 9mm cost enough to be worth reloading.

I think I've opined enough for now.

 

[Wise_A]

If you're looking for economical use of lead in a Glock, depending on the volume of your shooting, you may find that spending a few bucks per 500 on coated lead bullets beats buying a a new barrel.

That said, if you just want to justify an aftermarket barrel for your G-Lock, that's cool, too.

 

[SVT28]

Thanks for the writeup. Aside from the caliber war, what are your general thoughts about the Glock 40? Is it the MOS version and do you have some sort of red dot on it? Have you had any reliability issues with any of the ammo you've tested?

Thanks in advance
SVT28

 

[oink]

I haven't had any issues with any ammo so far with either barrel. I like the gun more each time I use it. Yes it is the MOS and I have a Venom Vortex on it with Ameriglo plain black co-witness sights.

I'm still getting used to red dots but I think I'm over the hump and my mind is starting to look for the red dot over the irons.

Ejection on the 40s and the anemic PPU 10s is marginal and they fall pretty close. It makes for finding the brass easier but makes me wonder how much margin of error they have from a stove or something. But all good so far.

 

[jack the toad]

Interesting post. I haven't shot that much but have wondered if most all regular factory 10mm was watered down to .40 S&W specs. I don't have that much experience with the 10 even though I've tried the G20SF, G29 and now G40 MOS with Burris FF3. Glock has been the extent of 10mm for me and the guns have performed 100% but since the 10 ammo seemed same as 40, I decided to try the 40 out of my 10. Extractor held shell in place and all fed thru the mag without a hitch. But since that achieved nothing other than ammo was cheaper than for the 10, I tried some Underwood which made the 10 come alive. I plan to keep my G27, 22 and 23 right along with the G40.

 

[BearBio]

I like Underwood hardcast in my G20 (aftermarket barrel).

Have a G22 and a G27 but converted them to 357 Sig. (I LIKE that load)

 

[oink]

I'd heard that you could shoot 40s out of the factory 10 barrel with the extractor holding the rim. But that just didn't seem like a good ideal to have bullets potentially bouncing off of the lip the 10s head space on, plus the potential for chamber erosion by having the hot gasses in that part of the chamber not protected by the 10s brass. I've seen what damage the gasses from a ruptured case can cause in a chamber.

The 40s do seem to benefit more from the longer barrel than what I expected. Lucky Gunner had the Barnes 140gr 40S&W doing 1037fps out of their Glock 27, 3.42-inch barrel while I got about 1140fps out of my Glock 40 with the 6.02" KKM barrel. That's a solid 100fps+ bump for about 2&1/2". I wonder what the Glock 22 would do at 4.49"?

 

[jack the toad]

I agree on not using the .40 in a 10 and only shot a few to determine if doable. No way I'd trust the difference in mag and chamber for serious work plus I have 3 glocks in 40 cal.

 

[oink]

When I talked to the guy at KKM I asked about mag issues with the 40s in the 10 mags. He suggested that the rounds be stacked towards the front to help assure proper feeding. I then asked if he had experienced any feeding issues with the 40s in the 10 mags or knew anyone that had. He said he had not and did not (he uses a 40 barrel in his own G40). I've been purposely stacking my rounds to the rear as I always have on all mags trying to see if I could cause a feeding issue. I haven't managed to cause one so far.

Side note: I called Glock about recoil springs, initially for the G40 but others as well. There are no other options for the G40 which is the same as the G20 (and Wolf doesn't make gen 4 or 5 springs yet). I also learned that I could send my older Glocks in for inspection and upgrade as I'm the original owner. I was surprised they were as old as they are. Time flies! The G21 Gen 2 is 1992, the G23 Gen 2 is 1994 and the G27 I thought was a Gen 3 is a Gen 2 1996. I guess I've been a bit of a Glockophile longer than I thought. But I still love my wheel guns and carried them far more than anything else although I also did the Smith Gen 2 semi-auto thing too and still have the 659 & 669.

 

[Wise_A]

There are a number of different options for converting your Gen4 to a Gen3 recoil spring assembly, including a non-captured spring if that's what you fancy.

 

[oink]

There are a number of different options for converting your Gen4 to a Gen3 recoil spring assembly, including a non-captured spring if that's what you fancy.

Maybe, if reliable. Wolf springs didn't mention anything. I'd be interested in hearing some options if you'd care to share.

 

[Wise_A]

I use a Taran Tactical guide rod adapter on my Gen4 34 MOS, along with one of their captured guide rods. The same adapter will work on Generation 5 pistols. TTI also sells uncaptured guide rods.

I can't recall any Gen 3 conversion-type guide rods that use Wolff springs, but bear in mind it was a couple years ago when I shopped it. No matter, the ISMI springs are quite good.

No problems with reliability, although the 34 is a tarted-up funtimes gun and not a carry firearm. The spring doesn't bind, it installs quite easily, and the guide rod adapter (literally a small ring) fits well. I wouldn't worry at all about it bouncing out. I use everything from light 147-grain loads, to more standard velocity 125s and 115s.

 

[7tenz]

I like Underwood hardcast in my G20 (aftermarket barrel).

Have a G22 and a G27 but converted them to 357 Sig. (I LIKE that load)

I got a G22 in the nineties AFTER I had accumulated a few 10mms. What was I thinking? Anyway it was around the time American rifleman ran an article about the "new" 357 sig 229 and I ordered a G22 barrel from BarSto in 357, and groups shrunk a lot over the factory .40 barrel without trying. I was only checking it for function when I got it not paying attention to accuracy at the time and when I looked at the target I was dumbfounded.

 

[roo_ster]

I'd gladly go full power if I could find what I wanted. I'd like a FULL POWER round that only penetrates about 12" but that expands dramatically to about an inch in that distance. Ypu'd think if they can get a lumbering 45ACP to 1" they could get a faster heavier 10mm to do it.

Underwood ammo is reasonably priced and they produce JHP and bonded JHP from 135gr@1600fps up to 200gr@1250fps. One of those will meet your specs.

 

[oink]

I use a Taran Tactical guide rod adapter on my Gen4 34 MOS, along with one of their captured guide rods....

Thanks for the information.