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Glock 29 kaboom

Discussion in 'The 10 Ring' started by deadandgone, Feb 2, 2013.

  1. MarineHawk


    Oct 23, 2011
    Okay, thanks guys for clarifying.

    I bought the KKM barrels primarily because I wanted to run lead rounds through them, and I've ssen too many people report problems with firing unjacketed rouds through the polygonal stock barrels to even think about taking a chance.

    I never had a single jam with my stock 4.6" Glock barrel in it brief use in my gun.

    I've never had a single jam wit my 4.6" or 6.0" KKM barrels.

    So, one can tell me that the KKM's are a wast eof money, which subjectively could be true--amatter of opinion. But, both of my KKMs (combined with 22l tunsten spring rod) have never jammed..

    They, at least in my hands, produce tighter groups--at least with the ammo I shoot. Not a scientific study to be sure.

    Alos, the main point of my question above is that don't the KKMs wrap the base of the cartridge a lot better than the stock barrels. I haven't taken pics, but it seems so for me when I compared, and I've seen similar pics from others. That's what I was thinkin gof, rather than a thicker barrel or chamber or superior metal.

    If either of my two KKMs had ever jammed once, I would worry that they are too tight. But since not, isn't it better to have more support around the base of the cartridge when you're getting up to high-10mm pressures? Or is that not material? I honestly can't say about the materiality of the lesser support. But two KKMs in my gun have never had a single FTF or FTE. So, I'm not worried about the tollerances being too high. Just wondering whether the additional clamping around the base of the cartridge might help prevent the base of the cartridge from rupturing and making the parts below that go "boom."
  2. It is great that you are ok. In years of shooting reloaded lead for my revolvers I found that the only problems with the guns were with reloads. When I hear of the FN 5.7, the Glocks kabooming it is almost always with reloads and probably non supported parts of the firearm. I will not shoot reloads in my semi autos. When I was twenty I was immortal but when over forty I want to be around and in one piece for a while. I am really happy that the only damage was to the firearm and your pride. Stay safe.:supergrin:

  3. deadandgone


    Jul 27, 2010
    Well I went out and shot about 5 rounds today. I was somewhat apprehensive as I was afraid I would jump and flinch like crazy. I thought I might dry fire awhile...then I thought first I'll see if I have a problem, then I'll dry fire.

    Don't have my G29 sf back yet, so I shot a few out of my xdm 40. Amazingly to me, all 5 rounds were in a circle of about 3 inches at 7 yards. So you know what? I walked away....knowing that there is more to do, but happy and smiling that the muscle memory is still there....I haven't lost it.

    As soon as I get my g29sf back from Glock, I'm going to send it off to Ken Hunnicutt of He did some work for me a while back on the glock that blew up, and I liked it. I want my gun back, but I want it to be mine as I knew it from before....when I shoot it again.

    On the way feels pretty good.

    And a thank you shout out to Shadow...thanks man.

  4. llll1lll1


    Aug 10, 2012
    I've had live rounds pop out when using a 40 sw mag with 9mm ammo in a 17. Perhaps you were using a 45acp mag in that 40/10mm gun?
  5. deadandgone


    Jul 27, 2010
    I get my Glock 29 sf back.....for something that hurt me pretty bad to be such a welcome sight....I guess it speaks to the human condition somehow someway.

    I took the gun out of the box, and lo and behold....Glock took my aftermarket parts, put them in a plastic bag, and sent them back. The extra power recoil springs, the Ghost trigger setup...all there as well as the 10mm 40 cal conversion barrel. And the recoil spring setup they sent back seems new...

    Unable to shoot due to terrible weather here in northern NC today...freezing rain, sleet, snow....yuck!!!

    I am , at this point, willing to let this thread settle down some. I just want to say thank you to Glock for their repairs and their exemplary customer service.

    And thanks to Shadow....for so many reasons.

    Swamp Fox ammo is still dangerous....who knows how much is still out there?

    I am alive, healing nicely...and I got my Glock back!!!!

  6. nickE10mm

    nickE10mm F.S.F.O.S.

    Apr 13, 2004
    Wichita, KS
    Great end to the story ... You even got your AM parts back! :cool:
  7. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    I am glad Glock worked with you to make your situation right at a reasonable price point!

    I hear you about the weather, today is our first day without rain/hail in many days, colder dry air is expected for the next few days, that should dry things up a little!

    Best regards!
  8. Life is good! :cheers:
  9. deadandgone


    Jul 27, 2010
    I changed the heading on this topic...I believe the main factor here is the dangerous Swamp Fox ammo...of which I am sure there is more...if the consensus is that I should not do this, well feel free...I just don't think it was a Glock thing

    Guess I can't do that...I changed the thread title, and a few minutes later it had reverted to the original title.....
    Last edited: Feb 27, 2013
  10. TDC20


    Apr 11, 2011
    Don't know if you've seen this one, a G31 (.357 Sig) KB'd with a KKM barrel. Chamber end fragged. Shooter OK, ammo mfg. covering the costs of replacing the firearm.

    These things happen...don't let it happen to you!
  11. deadandgone


    Jul 27, 2010
    I found out from Mike Cyrus(Lehigh Defense) who was talking to Kevin Underwood....Kevin seems to believe that Longshot can have pressure spikes in cold weather...kaboom happened in the winter with overloaded ammo.

    Another piece of the puzzle. Now the above information may or may not be true, its just an observation from an ammo manufacturer. Worth thinking about.
  12. Marshall8

    Marshall8 Guest

    Deadandgone, thanks for getting this back to page one. I am new to a G-29 and this forum had not read this thread yet. I got the Wolf 23# dual uncaptured spring and it has worked perfect from light to heavy loads. If I get a FTF in the future the first thing I will try is the stock 3 spring 17# RSA!

    Does anyone have experience where a heavy load would do anything negative like "smile" or FTF with the stock RSA then work perfect with the heavier RSA using the same barrel factory or aftermarket?

    Or has anyone worked up a hot load with the heavy RSA then put it into the stock RSA and experienced a problem?
    Last edited by a moderator: Mar 21, 2015
  13. texas 48

    texas 48 Gold Member

    May 19, 2007
    San Antonio, TEXAS
    What happened here is why I load every one of my rounds. I drop with a PACT powder dispenser and beam scale the 1st 5 rounds. Every dimension is checked to insure there are within SAMMI spec. At the end of 50 rounds I weigh each loaded round to avoid squibs and over charges. I will not buy from boutique manufacturers. as this example proves their QC procedures are suspect. This is for both .40 and 10MM ammo I make. Every once fired case is down graded by .1 gr I always start with new starline cases CCI primers and use 155gr XTP, 165r Golden Saber or 165r Gold dots and load a little longer than spec by by .001 or .002
  14. Happy you are okay, did you experience any trigger reset issues before the KB?

    I posted this pic shortly after joining GT, this Winchester casing bulged so far that it couldn't be resized; it was practice ammo.


    It was the last time I used a factory Glock barrel. I was rather Glock shy because it was about the same time a LEO had a G22 KB with department issued practice ammo.

    I've used both KKM and Lonewolf barrels in two G20s without any issues. There are no reasons to buy "real" 10mm ammunition, JHP bullets lose penetration at uber velocities.

    All the handloading manuals I have show downloaded powder data for unsupported 40S&W chambers.
    Last edited: Mar 21, 2015
  15. texas 48

    texas 48 Gold Member

    May 19, 2007
    San Antonio, TEXAS
    The hotest factory load by a large manufacturer is the Hornady 165 gr critical defense 1175/506 for.40S&W. For the 10 mm it's the same bullet @ 1265/550 or the 180gr XTP 1180/556.
    Book max for 155xtp with Longshot is 9.3 gr 1283 for th.40 I load mine at 8.8 1220ft/sec. I load 165gr Golden sabers or Speer Gold Dots with 10gr power pistol and get 1350f/sec w CCI 350 LPM can push to 1395/ 714 .Both bullets hold up well at that speed. No Glock smiles. Will only load that heavy with new cases.
  16. gator378

    gator378 Gator378

    Jan 22, 2001
    St. Peters, Mo, USA
    This is why I use Barsto barrels. Never had a problem. My 2 OEM Glock barrels were not so good. They bulged cases with factory ammo.
  17. TDC20


    Apr 11, 2011
    I did some calculations a while back and convinced myself that the recoil spring has almost zero effect on when/where/how the barrel and slide unlock, regardless of the pressure of the load. It is entirely a function of slide mass, which explains why the G20 and G29 slides are so much heavier than Glock's similar models in other calibers. What the heavier spring weight does do, is to slow the slide velocity on the way back towards the shooter, and increase the slide velocity as it returns to battery. However, smiles are the result of pressure and barrel support, not "early unlocking" as some have theorized. An early unlocking of the slide and barrel would be catastrophic, which is why Glock pistols are designed in such a way that it can't happen (because of slide mass). You will blow up the barrel if you keep increasing chamber pressure, but the barrel will blow before the slide and barrel unlock, assuming the gun is fired fully in battery.

    I'll also say that smiles in any barrel (Glock or AM) are over SAAMI pressure. I have fired all of my hot hand loads in the stock Glock barrels without any smiles. I know I'll stir up a lot of people here making these claims, but for your own safety, if you choose to shoot hot (nuke?) handloads (or boutique ammo), you should understand that things posted on the internet are not always safe and/or within the firearm manufacturer's design specification. Most guns can take a tremendous amount of overpressure without failing, but that's not what they were intended to do on a regular basis.

    To answer your question, no, the spring weight will not make a difference if your ammo smiles the brass or not. It will only help to keep hot loads from battering your frame. That is really the only benefit of heavier springs. Most people, myself included, perceive slightly sharper recoil when using a heavier spring.
  18. Taterhead

    Taterhead Counting Beans

    Dec 13, 2008
    Boise, Idaho
    TDC, I think this is a pretty good take on lockup. It is apparent that there is likely a lot of validity to what you're saying. It is educational to remove the slide and to trace the forces that act on the slide by 1) the RSA, and 2) the lockup mechanism that is caused by the case pushing against the breach face while the bullet is simultaneously pushing the barrel forward into the slide. The RSA is acting against the frame to push the slide forward, and the barrel acting against the breach to push forward into the slide. Tough to explain on the phone, but a few minutes looking at the system will show what I'm talking about. I am not an engineer, so could easily be corrected.

    I am not sure how much slide mass has to do with the system except to dampen the dynamics of the recoil event.

    I have not tried this, but my hypothesis is that the slide would stay locked under bullet discharge even without an RSA. Of course one would need to find a way ensure that the gun started in battery before firing. Perhaps this could be done by securing the gun upside down and using a mechanism to remotely activate the trigger.
  19. TDC20


    Apr 11, 2011
    You're mostly correct, Taterhead. Actually, the barrel and slide are locked together, but not from the force of the case pressing against the breech face. The locking is done by the locking block forcing the barrel into the slide, which is held in position by the slide lugs in the frame. The top of the barrel, where it is squared off, is also held in place by the slide. The barrel and slide can move back about 0.080" before the locking block (or it could also be called the "unlocking block" ) forces the barrel down out of the slide, allowing the case to be pulled free from the barrel by the extractor. Most people don't realize that the slide and barrel are in motion before the bullet leaves the barrel, but they are.

    I'm an engineer, but not a mechanical engineer. But back in my day, Universities required all Electrical, Mechanical, and Chemical Engineers to take a core curriculum including chemistry, physics, engineering mechanics (statics and dynamics), electrical circuits, and microprocessor programming. So, based on that, here is what I came up with, along with some factors which I know have an effect on the process, but which I considered small enough to be of little relevance...

    With a loaded round and the pistol in full battery, the primer and powder is ignited, creating a rapid rise in pressure. The pressure in the chamber forces the bullet down the barrel with a force equal to pressure (in pounds per square inch, PSI) times the surface area of the bullet. As a locked system, the behavior initially is one where momentum is conserved, or M1*V1 = M2*V2, where M1 * V1 is the mass of the slide and barrel times the velocity of such, and M2 * V2 is the mass and velocity of the bullet and powder, which has been converted to gas. This is a simple calculation that most every shooting enthusiast has used to calculate recoil velocity.

    If you measure the mass of the barrel and slide, and you know the velocity of the bullet (and powder, now converted to gas) leaving the barrel, you can calculate the slide/barrel velocity using the conservation of momentum equation. Now you can also calculate the acceleration of the slide using F = M*a. Since acceleration is a composite of the force from the bullet going one way, the force of the spring on the barrel and slide can be subtracted from the acceleration force. Spring tension is a function of Hooke's law, which means that the force increases as the spring is compressed more. Shadow has previously posted some great data on spring forces vs. where the slide position is. In battery, a 17lb Glock spring is something like 5 or 6 lbs, where a 22lb aftermarket spring is around 7-9 lbs. They are both close to their rating when fully compressed at the slide stop position. But even if you took the spring force to be 25 lbs in battery, it would have little relative effect.

    Anyway, when you look at the force of the spring in battery, it is about 1/5000 (or less) of the effect of the barrel and slide mass acceleration force in retarding the slide movement. Keep in mind that the barrel can not unlock from the slide until that 0.080" of rearward movement occurs. Now, if you have all your calculations in a spreadsheet, you can vary the bullet velocity, thereby varying the slide/barrel velocity. What you will see is that, no matter how fast the bullet velocity is, the slide/barrel can not make the 0.080" movement to unlock before the bullet leaves the barrel. It's a very elegant and safe engineering solution to send a projectile at high velocity, using extremely high pressure gasses, with no danger to the shooter...ever. Even in extreme overloading, you can't unlock the system before the bullet leaves the barrel. I ran my calculations up to 100,000 PSI, and guess what? The bullet is out of the barrel before the slide and barrel unlock! (More realistically is that the barrel ruptures, but that will occur with the barrel and slide still locked up)

    Some of the things that I simplified in my calculations are that I assumed linear acceleration of the bullet, which doesn't happen because the pressure curve that propels the bullet isn't a constant. Also, I did use a realistic mass for the powder (converted to gas), but only used a gas velocity equal to the bullet velocity, which I know is low. The gasses will exit the barrel faster than the bullet, but given the small mass, it turns out to be, not insignificant, but not dominant in the calculation, either. Friction in the gun system plays almost no part considering the forces at play during the dynamics of firing. I also only calculated to the point where the barrel begins to unlock from the slide, since that was the point of the whole exercise. Once the barrel unlocks, the exact dynamics of the system change, along with the effect of the recoil beginning to be transferred into the shooter's hand. This makes everything more difficult to model mathematically, but really at that point, what is a few fps in slide velocity? Maybe the difference in some frame battering.

    But I agree, Taterhead. You could fire a Glock with no RSA installed, and there will be no catastrophic failure, only a very rough stop of the slide bashing into your frame.
    Last edited: Mar 25, 2015
  20. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    Here are the measurements TDC20 was talking about for the Glock-20SF, this was with the non captive RSA from Wolff Gun Springs

    Glock 20SF spring test Wolff Gun Springs 22lb RSA installed
    It takes 6lb 4oz to start the slide to move from the locked position
    Full retraction at 22lb 9oz at lock open

    Glock 20SF spring test Wolff Gun Springs 24lb RSA installed
    It takes 7lb 6oz to start the slide to move from the locked position
    Full retraction at 24lb 1oz at lock open

    Glock 20SF Factory spring test
    It takes 5lb 3oz to start the slide to move from the locked position
    Full retraction at 18lb 0oz at lock open

    It doesn't take much pressure to keep a slide and barrel from unlocking either as you can place your thumb on the rear of the slide to keep it from moving...this was an interesting observation as well. An over sprung gun can change the cycling to the extent that it will not cycle correctly or at all.