Glock 10mm to .40 S&W Conversion


PDA






Fiero
September 28, 2004, 05:30 AM
I am looking to convert my Glock model 20 10mm to .40 S&W.

I've looked everywhere for any details on this matter and all I have found is a myriad of sellers of conversion barrels, but nothing else.

No instructions, no magazine reccomendations, nothing.


Anyone know of any details on the subject?

I've heard that the 10mm mags will work, but will .40 S&W mags work better???

It would seem that using 10mm mags would allow a lot of fore-aft play.

Last question... Is the reliability the same as stock? I mean, can I trust my life to the conversion relative to unconverted?

Thanks for any help.

If you enjoyed reading about "Glock 10mm to .40 S&W Conversion" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
ENC
September 28, 2004, 05:57 AM
No offense but why are you wanting to do it?

If it will be permanent just trade for a .40

Most factory ammo is loaded down to the same spec's as a .40.

AFAIK all you need is the new bbl and maybe mags but I don't see them as being absolutly necessary.

I have an HK that is convertible BW 40 and .357 and all I need to do is swap bbls.


Going from ten to .40 might also need a recoil spring.

SoCalGeek
September 28, 2004, 11:29 AM
I believe the way to go would be to (check on this first obviously, as i'm not sure) replace the whole slide/barrel assembly with that of a G22. I'd also change the mags just to be safe, but that's just me...

49hudson
September 28, 2004, 01:12 PM
All you need is a 40S&W barrel.
Glock model 22 is a smaller frame,so it's magazines won't work.
Glock model 20 can also be converted to 357sig with just a barrel change. Just be sure to seat the ammo all the way back to the rear of the magazine and it will function just as well as 10mm ammo does.
I have a Glock model 20C, with 6" hunting barrel and 40S&W and 357sig barrels and have never had a failure of any kind.
Can you trust your life on a 10mm converted to another caliber? That's up to you !

JNewell
September 28, 2004, 02:15 PM
I've done this very successfully. The "why?" question is worth asking, though.

I did it because I can buy .40 Short & Weak ammo for half the cost of 10mm or less, so it can be an attractive practice setup, at least part time.

All you need is the appropriate conversion barrel. The mags feed fine and in any case you can't use the shallower .40 mags in the 10mm/.45 frames.

I've never had a reliability problem, and I run the G29 with a slightly stiffer recoil spring. Have never had a failure to feed or any other type of failure.

As far as "trust my life" (your life, that is), yeah, probably, but why?:confused:

treeprof
September 28, 2004, 02:24 PM
I have a KKM .40 for my G20. It functions fine with all fmj ammo, plus Rem Golden Saber, Speer GD and Win SXT; I'd trust any of those for defense. I had some feeding probs with some old PMC Starfire ammo I was shooting up just to be rid of it, but nothing else. I'm not even all that careful to seat all the .40 rounds as far back as possible. I use a 22 lb recoil spring with all of them.

WhoKnowsWho
September 28, 2004, 04:04 PM
The KKM conversion barrel is $165 at www.lonewolfdist.com

Why not just pick up a turret press and start reloading for that amount of money? You could load the 10mm light or powerful if you want.

Fiero
September 28, 2004, 04:54 PM
Thanks Guys.

For those of you who asked why.

1. .40 caliber S&W is cheaper
2. The variety of ammo is greater(local)
4. The range that is closest to me will not even let me shoot hollowpoints, which is the only 10 mm ammo at the local Turners(gun shop).
5. I don't want to get into reloading.
6. I have hi-cap mags for my glock 20, which are legal in PRK, because I had them BEFORE the CALI ban.
7. If I buy a new Glock in 40 S&W, then it will have to be all lo-cap mag equipped.
8. It's cheaper to convert, than to buy a new gun anyway.


49Hudson brings up a good point agains the conversion though. I don't want to have to rely on a good "seating in the rear of the mag" to function correctly. What if I holster the weapon, and the ammo shifts forward in the mag? I guest I then have an unreliable jammer to protect my life with, eh?

treeprof
September 28, 2004, 06:04 PM
What if I holster the weapon, and the ammo shifts forward in the mag? I guest I then have an unreliable jammer to protect my life with, eh?

That's not my experience, but you'll have to test your preferred ammo on your gun to be sure. Why not carry 10mm, tho, as long as HP's are available, and use the .40 primarily for practice?

PO2Hammer
September 28, 2004, 06:34 PM
I highly recomend the KKM conversion barrel.
I have run several thousand rounds of .40s&w through my Glock 20. No problems. I've staggered the rounds front to back, all forward, weak hand only with a 20 pound recoil spring, no failures of any kind. Slide locks back as well. Only 10mm mags will work. No need to buy anything other than the conversion barrel.
The Glock 20 10mm/.40s&w combo is my favorite firearm ever. With Blazer Brass 180 fmj (.40s&w), I'm getting match grade accuracy (thanks to Heinie sights) and buttery soft recoil. I've also shot this combo in IDPA and improved on my Glock 34 9mm scores (qualifiers).
Stoked with 16 rounds of 10mm Wichester Silvertips, I feel just fine about home defense.
If I could only use .40s&w, I would have evry confidence in my 20. Hot .40s&w ammo is a real hoot to shoot (!) in the Glock 20. Corbon 135's are awesome and there is no snap when fired in the big 20. In a Glock 35, they can be 'stingy'.

agtman
September 28, 2004, 09:07 PM
I've got Federal Arms' drop-in .40 barrel for my G20 - and that's all I've needed.

The G20's stock recoil assembly and the stock 10mm mags (15rd & 10rd) work just fine with the .40 cartridge. The FA .40 barrel exhibits pretty good accuracy too (for a .40S&W anyway).

For the aftermarket drop-in barrels for the G20 in other calibers (e.g., .40, .357Sig & 9x25), some like KKM, Bar-Sto or Jarvis.

Clark
September 28, 2004, 11:06 PM
I have a Glock20 10mm and I am looking for a 40sw barrel for it.

Per my experiments, 40sw can be loaded to a higher velocity than 10mm, because of the large primer pocket is the weak spot.
A 10mm chambered for 40sw would be the best of all worlds, seating the 200 gr bullets long for the 10mm magazine, the hevier slide taking up more recoil, and the higher pressure 40sw brass.

JohnKSa
September 29, 2004, 01:16 AM
Clark,

You GOTTA post more background information when you make a statement like that. Not everyone knows you blow up guns for fun...

BTW, if you're interested in an unfired FAC aftermarket .40 S&W SS conversion barrel for the Glock 20 pm me.

JNewell
September 29, 2004, 02:28 PM
That's not my experience,

Nor mine, but I've never tried shooting anything but cheap .40 ammo in my 29.

I'm half embarrassed to admit it, but in light of my goal (cheap practice ammo, therefore need as little investment in the barrel as possible to amortize with the difference), I went with a FAC barrel. I'd have to say that it way outperforms my expectations on both accuracy and reliability (again, though, only tested with ball range ammo).

Zak Smith
September 29, 2004, 03:18 PM
The standard gun for "Limited" class in USPSA/IPSC is a double-stack 40SW on a SV/STI 1911 platform. Since this action is long enough for 38Supe or 45ACP, we have the fore/aft play issue.

The solution most of us use is to just load long. My SV will chamber and feed rounds out to 1.230", which is probably longer than what your Glock will accept.

If you have a 40SW barrel for your pistol with a long enough throat, you could do the same.

Or just handload 10mm. Modulot the brass cost, it'll cost the same as loading 40SW.

-z

agtman
September 30, 2004, 09:36 PM
"*** 40sw can be loaded to a higher velocity than 10mm, because of the large primer pocket is the weak spot."


:rolleyes:

Well, let's see. Case length: 40S&W = .850; 10mm AUTO = .992.

Hmmm, ... guess that's what's called a KABOOM! - right?

Zak Smith
September 30, 2004, 09:55 PM
Case length isn't the real issue; it's the loaded cartridge OAL.

I.e. what's the difference between a 40SW loaded to 1.200" and a 10mm loaded to 1.200"?

The 10mm will actually have more initial friction because the case has more contact with the bullet.

-z

Clark
September 30, 2004, 10:42 PM
This is a picture of some 30-30 brass I cut down and shot in a stock Glock 20 10mm barrel. Because the brass is thicker, a higher pressure can be reached before the brass fails, and so produce higher velocities than ordinary 10mm brass in that barrel. But becuase the internal volume is less, 40 sw brass can reach higher velocities at with a barrel with good case support.

http://www.thehighroad.org/attachment.php?s=&postid=274851

NorCalFlyer
September 9, 2006, 11:12 AM
I have found a couple of conversion barrels... the Fire Dragon (ported) and some others. I am wondering about the reliablity of each, so if anyone has these or has heard of any issues I would like to know which ones not to purchase.
Thanks.

envonge
May 1, 2007, 06:11 AM
Can someone link me to some good conversion barrels for the Glock 20 in the following calibers:

.40 S&W, .357 SIG, 9x25

Thanks!

Vitamin G
May 1, 2007, 09:43 PM
Per my experiments, 40sw can be loaded to a higher velocity than 10mm, because of the large primer pocket is the weak spot.


Huh????

Clark
May 1, 2007, 11:30 PM
Yeah!!

medmo
May 2, 2007, 06:02 AM
Clark,

What pressures are you running?

GARY1911A1
May 2, 2007, 08:22 AM
I would guess if one had feeding problems of .40 in a Glock 10MM Magazine a spacer in the back like used on 9MM and .40 1911 magazines might solve the problem. A sheet of plastic of the correct thickness cut to the inner deminsions of the rear where the number holes are might work. You couldn't see how many rounds unless you cut holes for them too. I say try .40 in the 10MM Glock Magazine first.

the pistolero
May 2, 2007, 11:11 AM
I don't want to get into reloading

For something like 10mm, it really would be your best option, though, and you'd also be able to shoot more in your other calibers as well. And it's not hard...it just gets addicting. :D

Vitamin G
May 2, 2007, 06:42 PM
Wait... didn't someone named "Clark" get the reloading forum shut down awhile ago for posting ridiculously dangerous loads at the 1911 forum?

JohnKSa
May 4, 2007, 12:36 AM
Vitamin G,

Read post #13 on this thread. It is not intended to be humorous nor sarcastic. Clark does his own version of failure analysis on his personal handguns. While he has explained his techniques with caveats on other threads in this forum, he is often strangely reticent to post disclaimers to go along with his outlandish assertions--which, I might add, are only outlandish if you don't know what his hobby is.

D51208
December 14, 2011, 10:42 PM
Hey guys i just got a glock and the ammo is ridiculously expensive! Good thing i hand load. Converting 30-30 to shoot in a 10mm, is it safe and/or better than regular 10mm cases? Whats the process?

The 40 S&W, if it is the right overall length, can it safely be shot from a 10mm bbl?

Right now i have 180gr hornady xp bullets and titegroup for powder. I'm ordering lee dies and starline brass sometime here soon. Any suggested loads?

GLOOB
December 14, 2011, 11:09 PM
For those that don't know, Clark TIG welded the ramp of his Glock 22 barrel and recut it to provide full 360 degree support around the entire case, right up to the web. And he's not afraid of voiding his warranty or blowing up the occasional $500.00 firearm in the name of science.

So if you want to spend the time and money to prove him wrong, then go ahead and do it. Until then, why not just take him at his word? (And stick to SAAMI specs for your own reloading!)

Bovice
December 14, 2011, 11:27 PM
For the love of God, don't be hacking up .30-30 brass for a 10mm.

You need to either pony-up and buy some 10mm brass and load it on your own or trade for a G22. The 10mm they sell off the shelf is extremely similar to .40 S&W but at a much higher price.

You can't expect to not reload your own ammo when you buy a gun with an obscure chambering.

tlen
December 14, 2011, 11:35 PM
Get a LWD 10-40 barrel and use standard G20 magazines. .40 S&W Glock magazines don't fit the G20. No need to change recoil spring; stock works fine. You can get a 6" or a stock length 10-40 barrel. The longer barrel works fine and will give you ~100 FPS more velocity if that is important. With a LWD barrel you can shoot cheaper lead .40 S&W ammo as well.
The added G20 weight makes shooting .40 S&W feel like 9mm.

Fatdaddy
December 14, 2011, 11:36 PM
My G20c with KKM 10-40 conversion bbl worked flawlessly, same springs, same mags. I bought it because I got tired of losing my 10mm brass in the weeds.
Plus it looked cool, shiney bbl visible through the factory porting.

http://i693.photobucket.com/albums/vv297/lowangz/g20ctop.jpg

sargents1
December 15, 2011, 03:21 PM
Hey guys i just got a glock and the ammo is ridiculously expensive! Good thing i hand load. Converting 30-30 to shoot in a 10mm, is it safe and/or better than regular 10mm cases? Whats the process?

The 40 S&W, if it is the right overall length, can it safely be shot from a 10mm bbl?

Right now i have 180gr hornady xp bullets and titegroup for powder. I'm ordering lee dies and starline brass sometime here soon. Any suggested loads?
Listen to Bovice.

I am not sure how you think you can make 10mm brass out of 30-30 brass anyway. 10mm has a rimless design (where the case head rim is flush with the sides of the cartridge body) and 30-30 has a rimmed design.

I doubt you could safely make 30-30 brass into 10mm brass, and even if you could...Why would you when 10mm brass is the SAME price as .40S&W brass?

Starline Brass 10mm Auto is $85.50 / 500ct.
(http://www.starlinebrass.com/index.php?cPath=1&osCsid=5bf9adaf2d9e6c8b198fe2c8e2ead65f)

Starline sells .40s&w brass for $81.50 / 500ct.

As for shooting .40s&w ammo thru a 10mm Auto barrel...
It is probably safe (probably being the operative word here).

10mm runs as high as 37,500psi where .40s&w runs 35,000psi. But automatic cartridges headspace on the mouth of the case rim. Meaning, it is the case rim that stops the cartridge from going too far into the barrel/firing chamber. So you could theoretically chamber a .40s&w cartridge and it might fall too far into the chamber for the firing pin to contact it.

I have heard of folks doing this, but I will NOT be doing it with my G20. There is no compelling reason to do it, and it may not be safe. I dont know All of the particulars and just because it seems like it should be safe doesnt mean it is.

Bottom line: If you want to run .40S&W thru your 10mm glock, spend the 125$ - $165 dollars for a Lone Wolf or KKM conversion barrel.

Now, if there is a Zombie Apocalypse and all I can find is .40S&W ammo, and I MUST use .40 in my 10mm I will do so. But, barring some supernatural emergency I will be using proper ammo.

Zak Smith
December 15, 2011, 03:40 PM
The right way to do it is to get a .40SW-10mm conversion barrel. It will then headspace properly.

I have shot some .40SW rounds out of my 10mm Glock (with 10mm barrel) to see what would happen but I recommend against doing that.

GLOOB
December 16, 2011, 12:44 AM
I am not sure how you think you can make 10mm brass out of 30-30 brass anyway.
Methinks you didn't read all the posts. Like post #18. I'm pretty sure it CAN be done.

R.W.Dale
December 16, 2011, 03:05 AM
Case length isn't the real issue; it's the loaded cartridge OAL.

I.e. what's the difference between a 40SW loaded to 1.200" and a 10mm loaded to 1.200"?

The 10mm will actually have more initial friction because the case has more contact with the bullet.

-z

There is much sense here.

I've personalty not done it but folks have loaded 10mm on 40 brass loading to the same col as 10

This may seem insane but as Zak points out internal case capacity is the same on a stronger small primed case

posted via tapatalk using android.

Zak Smith
December 16, 2011, 03:10 AM
A stronger/heavier case would probably have less internal capacity when loaded to the same OAL.

R.W.Dale
December 16, 2011, 03:38 AM
A stronger/heavier case would probably have less internal capacity when loaded to the same OAL.

Agreed. You could easily verify this by cutting a 10mm case down and comparing the case cap in grs of h2o to a piece of 40 brass

You'll also need to ensure your 10mm 40 conversion barrel is throated to accept the longer than saami col

You'd definitely want to fine tune and probably dial back a bit. But it wouldn't be the instant KB you'd think at first glance.

posted via tapatalk using android.

Zak Smith
December 16, 2011, 03:41 AM
I got KKM to make me a .40SW-10mm conversion barrel. It has enough throat to shoot my USPSA "Limited" .40 rounds, a 180gr JHP at 1.23" in .40SW brass.

N43122
January 17, 2013, 03:29 AM
Hey fellas,

I've made these insert spacer plates that fit in the Glock 20 magazine that allow a .40 S&W to feed perfectly by pushing the .40 S&W round forward by .095" Keeps the rounds from shifting around inside the mag. Holes are milled into it to still allow mag capacity check. Direct drop in, non-destructive.

If you enjoyed reading about "Glock 10mm to .40 S&W Conversion" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!