Glock 20 bbls: Stock bbl vs. Aftermarket bbl?

Discussion in 'The 10 Ring' started by pasky2112, Aug 6, 2012.

  1. pasky2112

    pasky2112 Senior Member

    Hi Everyone. :wavey:
    Forgive me for starting a new thread on this subject but I've been reading GT for many days...literally...researching this topic. I see a VERY wide range of responses to the below questions that I'd like to propose they be aggregated in this thread.

    To the point, I have a new G20 (my first 10mm) coming and planned to just shoot it stock with some factory loads (PMC) and then reload those and handload some new Starline and Win brass. But I keep seeing pictures of blown cases, glock smiles and the like from folks loading hot/nukes in a stock Glock bbl. Since 10mm brass isn't laying all over the place like .40 S&W, I'd like to preserve the ones I buy best i can using the bbl I paid for with the gun. ;-)

    That said:
    If one likes to load hot, would it be better to get an aftermarket bbl with a 'better' chamber? I use a KKM in my .40's just to preserve brasslife...I'm not sure they are more/less accurate, IMO. Any preferences/experience re: AM bbls like SL, KKM, etc.?

    I'd like to work up safe max loads in .40. Can I shoot reloaded .40's out of the G20 stock bbl RELIABLY /ACCURATELY... relatively? ;-)

    Since quite a few shooters report they shoot .40's out of their stock and/or AM 10mm bbl's, what's the point of conversion bbls?? :dunno:(10mm-.40, that is) Is it the 'use it for what it's designed for' principle?

    Has anyone ever just dropped in a 6" AM bbl in place of the stock G20 4.6" bbl and felt it shot well? ...better? Why did you swap bbls?

    Thanks to all in this forum and everyone sharing their experiences!

    Wanna kill these ads? We can help!
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  3. Taterhead

    Taterhead Counting Beans

    Congratulations on the new G20. You will love it.

    I'll cut right to the chase, "going nuclear" is a risky proposition no matter what barrel you use. I have spent a lot of time loading for and shooting rounds through my stock gen 3 G20 barrel. The single biggest factor in safety is your loading practices -- not the barrel. I personally would not shoot a load in an aftermarket barrel that I deemed unsafe in my stock barrel. A little mentioned fact is that tighter chamber dimensions of aftermarket barrels can actually result in higher pressures.

    200 grain handloads @ 1200 + run great in the stock barrel. All of the Buffalo Bore, Underwood, and etc. are safe in the stock barrel. I get an average of 9 reloads. Hot loads are loaded into new brass, then they are relegated to the reload assortment.

    For the cost of a new AM barrel, you could buy at least 1000 new pieces of brass from Starline.

    If shooting .40 is part of the future plans, that is a reason to get a new barrel. For sure. I see shooting .40 S&W out of my G20 barrel as one of those "can do" things in an emergency.

    I was poping primers from a couple hundred .40 S&W brass in my G20 over the weekend (long story). I was loading them from mags and manually cycling the slide. One thing I observed was that the striker occasionally pushed the case forward into the chamber such that it popped out of the extractor. I could envision how a loaded round, upon iginition, would be shove the case back against the breech and slam it into the extractor. It would function ok, but it just seemed to potentially be a lot of wear and tear. There was more fore-and-aft movement than I expected. I had to get out the squib rod a few times to clear the case from the chamber.

    #2 Taterhead, Aug 7, 2012
    Last edited: Aug 7, 2012
  4. Let me start by saying I am a newbie to 10mm loading. Guys like Taterhead, Yondering, Shadow, Meathead9, Robert91922, et al have probably forgotten more about loading this round than I will likely ever learn.

    My experience is that my KKM barrel's provide a small improvement in chamber support, but I personally don't think it is a required improvement if you are staying anywhere near sane loading (I am talking specifically about Glock 20/29 here, the difference in my KKM and stock G21 barrel is more pronounced).

    My personal opinion is that smiles occur when you are over the pressure line and occur more because of timing issues than because the stock ramp is cut too far into the chamber or the chamber is too loose. I do think tighter chambers can cut down on how far a case stretches, so may help with brass life, but at $.15/case for new Starline, I think you would have to shoot a great deal of extremely hot loads to make up the price difference of what an aftermarket barrel will cost and save you in cycles.

    I bought a KKM 10-40 conversion barrel for my G20SF. I have shot alot of 40 loads through it and it works perfectly in that application. My 10-40 barrel came as a non-dropin (I had to fit it) and also had a generous freebore already cut in it. I suspect this barrel was intended for a smith as I needed to fit it and likely was originally destined for a competition shooter who planned to shoot a long loaded lead (hence the freebore cut). I fit it to my slide (not as well as a smith probably could have done) and it works fine. With the generous freebore that my barrel came with, I have been able to load my 10mm loads with 40S&W brass (basically more powder and longer OAL like a 10mm round) and shoot them through my conversion barrel without a hitch. It was after that experience that I tried shooting 40 and 10mm loaded in 40 brass out of my stock G20 and G29 barrels, they feed and shoot perfectly. The one caveat I do have to say is both of my G20SF's and my G29SF are newer guns and the mags are also newer. I think no magazine I have has shot more than 3-4K through it, so the flawless feed of 40 brass through my 10mm barrels has to be kept in perspective, I don't know if the flawless feeding will continue when mags start to wear and actions start loosening up.

    I guess all of the above is a lot of anecdotal blather to say, hold off on an aftermarket barrel for a while, stay inside the lines loading hotter 10's until you get familiar with the gun, the brass, the powders you are using, etc.

    The 10mm is a wonderful round, whether loaded in 10mm brass or 40 brass, enjoy the ride and don't be in a rush.
    #3 WeeWilly, Aug 7, 2012
    Last edited: Aug 7, 2012
  5. I have a question for the guys shooting 40's in their stock G20 barrels - are you using stock recoil spring or does it have to be lightened to get it to cycle right.
  6. No problems with stock or even the 22lb RSA.
  7. dm1906

    dm1906 Retired SO

    Ditto. No problem with the stock spring (about 4-5' ejection), or a 24# spring (measured 24.25#). With the 24 pounder, the brass just dribbles out, but they do, every time.
  8. Which of the aftermarket barrels are preferred, or does it matter for which reason (accuracy, reliability, support, etc.)? I don't know if I will get into reloading yet but am interested in chamber support for saving my bacon (no exploding G29's, thank you!). I also totally want the ability to shoot .40 and .357 Sig and make the ultimate gun even more ultimate...but so many barrel makers.
  9. In my home. The sad truth is. If it's a Glock it's barrel and chamber are worthless.

    Support has got better. But it's still on the weak side, truth be known. What gets me is there $2.00 whore loose chambers. Glock can go on and on with it's loose to be fail safe. "A Glock will always chamber a round" crap all they want. The hole is just to darn big. I cant think of a combat pistol one with a chamber as big as a Glock in any caliber. Just tighten up a solid .002 Glock!!!!!

    One day they will do right. :)
  10. Yeah, those dumb Glock guys, idiots, really... :whistling:
  11. Care to explain your coolaid Wee? Make your case concerning Glocks whore loose chambers compared to it's faulty to elite competitors.
    #10 blastfact, Aug 9, 2012
    Last edited: Aug 9, 2012
  12. dm1906

    dm1906 Retired SO

    Yeah. Those idiots ain't got anything right. Dumb. Really dumb.
  13. pasky2112, when you get your G20, pull the barrel out, and drop a round into the chamber. Take a look at the feed ramp, and notice how much of the round, above the extractor groove is exposed. If it looks to be excessive, that may be a problem with hot loads. If it looks only marginally, more exposure, from the rest of the brass, you should be fine. You won't know anything for sure, until you have ran some rounds through it. If you see bulging in the factory PMC ammo, the bulge will be worse with hotter loads! Again, you will need to fire the G20, before a decision is made to whether or not an after market barrel is in order.

    I do not shoot 40 through my 10MM's! I reload, and sounds as though that is in your plans also. If that is the case, there is no reason whatsoever for a 40 conversion barrel.
  14. pasky2112

    pasky2112 Senior Member

    I got to shoot my new G20 for the first time last weekend! Now I can see what everyone is talking about. I don't understand the "FBI...Heavy Recoil" thing. It shoots just like my hot .40's in my G22 Gen4. I even let a kid (~12 y/o) next to me try it for HIS 1st time and he hit a paper plate @ 15 yds! We were both sych'd!
    I shot some my 'hot' .40's (180g @1100 fps) from it in the stock bbl and there was only a minor decrease in felt recoil/target re-acq from the factory PMC 200gr loads in 10mm. Both shot where I aimed @ 15 yds though I had more 'fliers' with the .40's which I expect was d/t the short COAL in the 10mm chamber. Some folks mentioned they load .40 brass to 10mm (OAL+charge). I may increase the OAL to minimize the jump into the leades. Then maybe I'll work up a charge. But the point is the factory bbl worked fine for both loads...functionally and how I'd expect. I love it! Gonna hold off on the AM bbl for now. I have a 22# SS RSA on order, although the stock RSA functioned fine. I want something to keep my slide closed a bit longer and keep my brass closer. ;) Also, I'm a lefty so a new extended slide stop is on order. VERY PLEASED with this gun!
    Thanks a ton for everyone's input and other threads.
  15. Great news.

    I load 180gr jacketed to 10mm lengths using 40 brass for my G20's and G29. I use 10.5grs of Blue Dot loaded to 1.255" as a reasonably inexpensive plinking round.

    You will want to get in the chamber with a brush and some CLP to clean it well after a session of shooting the 40 brass, kind of like when you shoot 38spl brass in a 357, a little fouling in the chamber.
    #14 WeeWilly, Aug 13, 2012
    Last edited: Aug 13, 2012
  16. pasky2112

    pasky2112 Senior Member

    That's EXACTLY the application I want to do in the stock 10mm bbl. ; shoot .40's in my 10mm like 38spl in a .357mag. I have a TON of 40 brass. So shooting the 10's will be a 'treat' and the .40's will be for practice of fundamentals, etc. The .40 feels nice in the FS G20 with that big slide. I imagine a 22# RSA will smooth it out even moreso. Even if the only benefit is that my brass doesn't eject as far, I'll be happy. Honestly, I hate wasting time chasing down my brass when I shoot. It's all good, though. :)
    Another obsession I have is a clean and appropriately lubed weapon. So I clean my chamber and bore after every shoot...20 or 2000 rnds, doesn't matter. So a little extra time in the chamber... no prob. ;-)
    A little OT but I've always avoided lube (CLP) in any chamber, though. Doesn't that increase the risk of 'backslapping' the case against the breechface? Increases slide/bolt stress? Thanks for the load tip for the .40 in 10mm. Do you use SP mag primers or std in your .40 brass?
    Again, thanks for sharing!
  17. I have always cleaned my rifle chambers of any residual oil, but that was for pressure concerns.

    I have never been as meticulous with my handguns regarding traces of any residual oil in my chambers. I have not noticed any negative effects, but maybe I have not been looking close enough ;)
  18. JBnTX

    JBnTX Texas

  19. dm1906

    dm1906 Retired SO

    No risk, as it may be in other auto-pistol designs. The feature that allows you to shoot .40's in your 10mm barrel, is the same thing that will prevent this. The rounds, when chambered, are firm against the breech, held by the extractor. If it didn't do this, the .40's wouldn't fire. The Glock slide is the "bolt", one piece.
  20. samurairabbi

    samurairabbi Dungeon Schmuck

    There are headspace tolerance considerations. There is far more play in the gap of the extractor holding the rim than there is in the chamber holding the cartridge MOUTH. That is equivalent to much greater headspace variation, even if the .40 round DOES fire consistently. Field strip a Glock, place a case in the extractor, and wiggle it fore and aft. THAT amount of wiggle is now the headspace variation. Would you tolerate that much headspace variation when shooting 10mm in a 10mm factory barrel?

    "Getting along" with shooting .40 in a 10mm barrel is something I did (before scrounging conversion barrels), but I never contend it is an equivalent condition to shooting 10mm cartridges.
    #19 samurairabbi, Aug 13, 2012
    Last edited: Aug 13, 2012

  21. The 10mm PMC ammo is not a very hot load. Order some real 10mm loads from Underwood to get a feel for what your new G20 is capable of. There is a difference you can feel but by no means is it uncontrollable. I was very pleased with mine and am anxious to try 40 loads as they are much more available at far less cost.
    #20 copo9560, Aug 13, 2012
    Last edited: Aug 13, 2012

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