Who's the #@%&* who told me I could shoot .40s&w out of my 10mm bbl?

Discussion in 'The 10 Ring' started by G29SFWTF, Sep 18, 2012.


  1. So I can shoot .40S&W, no problem with stock barrel and mags?
     

    Wanna kill these ads? We can help!
  2. vaquero aleman

    vaquero aleman "ah-lay-mahn"

    915
    0
    386
    I loaded the 40 into factory G20 mags, which of course fit in my G21 because the frame is the same as the G20, and other than a little sliding back and forth in the mags, of the cartridges, there appeared to be no problems. Of course these are just my results.

    I am in no way warranting the use of 40 S&W in a Glock 20 or 21, it is a personal choice. Do so at your own risk.

    And don't tell Gaston about it, they are kinda fussy about those things.
     

    #62 vaquero aleman, Jan 19, 2013
    Last edited: Jan 21, 2013
  3. Can .40 be shot out of a stock 10mm EAA Witness?
     
    #63 gofastman, Jan 27, 2013
    Last edited: Jan 27, 2013
  4. Look at it and see. You want to be sure that the firing pin can't hit the primer if the case is ahead of the extractor, which would allow the gun to fire out of battery. You also want to be sure that the extractor is heavy enough to take the force of the firing pin strike repeatedly. I have heard of one person who did what you are suggesting, but have no experience at all with that pistol, so could not say whether it is safe or not.
     
  5. It is not a good idea. Just like a 1911 and most other 10mm pistols, the firing pin is long enough to set off the round, even if it is in front of the extractor. This causes the case to slam back against the breech face, and sometimes results in case bulges and possibly ruptures. You'll also notice a spot where the case rim gets sheared off, as it's forced past the extractor (towards the rear) at high speed.

    The Glock is the only gun I know of where this is a safe practice.

    I will admit to doing this with my Witness back when I had one, to find out what it would do, and have never seen or heard of damage to a gun or shooter from it, but just judging from the appearance of the brass, I wouldn't do it any more.

    In the Witness, when (not if) a round jumps the extractor, you'll see fired brass like this:
    [​IMG]
     
    #65 Yondering, Jan 27, 2013
    Last edited: Jan 27, 2013
  6. Just thought I'd stop in and report my experience.

    Gun: Gen 3 G20SF (2012), stock barrel, stock recoil assembly.
    Ammo: Federal Champion 40 S&W, PMC 200 gr. 10MM.

    Was shooting at a ~8" bullseye target at 10 yards. All rounds chambered and fired without any problems. However, the accuracy seems to have suffered significantly. I fired 10 rounds of 10mm, all rounds grouped ~3". I then shot 10 rounds of the 40 S&W, all rounds hit ~4" lower than the 10MM rounds and had an ~8" group. Thinking that I was probably just nervous, I put out a new target and tried again. 10 rounds 10MM, followed by 10 rounds 40 S&W. The results were similar, I didn't see any keyholing but the grouping was definitely low and loose.

    Nice to know that the 40 S&W will work in a pinch with the stock barrel, but I'm not going to make a regular practice out of it.
     
  7. Bren

    Bren NRA Life Member

    Yep, it will work until it doesn't. I'm not sure, but I would think it could result in the case head separating and some brass and crap blowing out of every hole, sooner or later.
     
    #67 Bren, Jan 28, 2013
    Last edited: Jan 28, 2013
  8. It is not difficult to use a conversion barrel. I use a Lone Wolf 10mm-40S&W conversion barrel and the original 10mm mags. :beer:
     
  9. Sooo your saying i can get a g20 / 10mm conv. to 40s&w & shoot it in my g21 slide ? :wow:
     
  10. vaquero aleman

    vaquero aleman "ah-lay-mahn"

    915
    0
    386
    I don't see why the 10mm to 40 conversion barrel wouldn't work, but I am not an expert or gunsmith. I very well intend to get a conversion barrel for my 21. I would rather have it and not need than the other way around. 40 S&W is easier to find than 10mm for sure. And, in most cases, cheaper. I picked up a 100 round value box of Rem 40 at walmart when everything else was sold out.
     
  11. The reason i ask is i have a g21 / 10mm storm Lake barrel & i couldn't find a g21 / 40 s&w conv. barrel. I don't think they make one, at least Storm Lake dosen't.
     
  12. vaquero aleman

    vaquero aleman "ah-lay-mahn"

    915
    0
    386
    I have to agree, I don't think that a 45 to 40 conversion exists but I will be buying the LWD 10 to 40 conversion when they finally get it in stock. $109 plus shipping is a whole lot cheaper than another gun.

    And, I finally got some Underwood 180gr TMJ 10mm and that is what I am now carrying in my 21. I have some questions to be answered about my slide before I continue shooting .460 Rowland. I should be getting about 1425 to 1450 fps from my 6" barrel. Pretty hot!
     
    #72 vaquero aleman, Jan 28, 2013
    Last edited: Jan 28, 2013
  13. Well, you will need some magazines. The 40S&W, 357 SIG and 9x25 Dillon will feed in a Glock 20 10mm magazine. I would not trust the 21 magazine to be reliable with those calibers.

    I also wonder how reliable the extractor would be. The 10mm Glock 20 conversions I see all have the same base diameter. It may work fine like my Glock 27 40S&W-9mm conversion, in which I change the barrel and use 9mm magazines.
     
  14. vaquero aleman

    vaquero aleman "ah-lay-mahn"

    915
    0
    386
    I got two G20 mags when I bought the 6" barrel. And after I shot the 40 I found that I had to do the "KKM" conversion on my extractor. I shot some 10mm after that and everything was ok, but I haven't had a chance to run any more 40 through it. Also, it's not as positive an ejection as the 45 but the 40 does eject when I cycle some by hand.

    But, to get back to the OP's point, I did pick up a value box of Rem 40 S&W JHP that I intend to run through my factory G20 6" barrel. I want to see if the mod to the G21 extractor will fix the ejection problem with the 40 caliber rounds. And I need to see if maybe their might be a problem with the Underwood 135gr primers being a little too hard.
     
    #74 vaquero aleman, Jan 28, 2013
    Last edited: Jan 28, 2013
  15. For the record, I shoot .40 out of my 10mm 1911 frequently.
     
  16. Do you ever look at the fired brass? It would be very surprising if you don't find any that look like my pic above. It really is not a great thing to do on a general basis, except in a Glock.
     

Share This Page