Glock 20SF Frame getting beat up?

Discussion in 'The 10 Ring' started by AstraPat, Apr 1, 2012.

  1. Hey all,

    I have had this 20SF since last fall (RVH Prefix) and have 350 rounds through it. All handloads, Mostly 180XTP's 9.0 longshot 1250fps, and 9.5 Longshot 1290fps. I have been using the stock RSA half the time and a ISMI 22lb on lonewolf dist SS guide rod the other half.

    I just returned from a camping trip and put 50 rounds of 9.0 longshot/180XTP through her with stock RSA. I have always noticed the point of contact where the slide meets the frame during full rearward slide travel. knowing that there is not a lot of surface area where they meet as well as the power of this cartridge. I looked again this morning when I was cleaning it.

    It appeares that this area on the frame just forward of the fwd frame rails is taking flogging. it is exponentially worse than only 50 rounds ago. The LH side is worse than the right with the crack, but both sides have the polymer showing stress.

    I am looking for ya'll's advice/counsel on what to do with this. Start the "call Glock process"?, or just shoot & monitor this area of the frame?

    I will try to get a few more pics.





    Wanna kill these ads? We can help!
  2. I'm pretty sure that's a clue that your handloads may be too hot for your setup. QL shows a potential pressure of in excess of 46000 psi for the 9.0 load. slide looks like it's battering the frame

    I'd contact glock tell them whats happening and what you've been running thru it. they should fix you right up.

    #2 Ethereal Killer, Apr 1, 2012
    Last edited: Apr 1, 2012
  3. ChuteTheMall

    ChuteTheMall HildabeastHater

    Or, send it to me with your handloads and I'll let you know later.

  4. That's weird, because Hodgdon shows a max of 9.5gr @ 34,6000psi.
  5. True, cause of the velocity I am getting along with normal glock bulging. No smiles, or flat primers.
  6. Think I'm just going to shoot it with the 22lb spring, and monitor that area.

    it's just weird because I hear of you guys putting 1000 plus rounds of hot loads through your 20's, and I haven't really heard this talked about a lot. Maybe it's just not that bad?

    I doubt the 29's show that kind of stress on the polymer due to having so much more surface area where the slide contacts the frame on rearward travel.. At least my 30 does.
  7. Javelin

    Javelin Got Glock?
    Silver Member

    That sucks.

  8. Yeah there's no way you're over SAAMI max pressure with a mid level published load. I have shot 600rds of 180's over 9.2gr Longshot, along with around 400 more of really hot stuff through my G20LS. The heavy longslide should beat the frame up even more than a factory slide, so I'll check my frame when I get home. I haven't noticed anything that concerns me so far, so hopefully that "wear" is normal for Glocks. Some Glock frames have weird looking insides just from variances in the molding process. The subcompact G26/27's are a good example.
  9. who knows what the brass capacity is vs what he's got. Lord only knows what he's got going on with the chamber and slide and barrel and seating depth and primer and powder lot and actual spring weight, etc etc etc. too many variables to say "the load is good to go".

    in any event the obvious damage points to the load being too hot for the gun setup, and that is a definite sign of "too much pressure" regardless of actual pressure. It's kinda that simple.
    #9 Ethereal Killer, Apr 2, 2012
    Last edited: Apr 2, 2012
  10. Just ask!

    Bone stock 20SF, except running ISMI 22lb RSA 50% of the time.

    New starline brass for 9.5 Longshot loads
    Once fired starline for 9.0 longshot loads
    180 XTP's
    1.260 oal
    All individually weighed

    Most of the 350 total rounds fired have been the 9.0 load. Fired brass at widest point measures .433

    I agree with the obvious damage, Im just not sure it's due to this 180gr, 1250fps, no pressure signs on brass, middle of Hodgdon's min and max load.

  11. Well because of this post I just opened up my six month old 20sf with maybe 4-5 thousand rounds through it. Almost all rounds have been total powder puff .40sw type loads. I've shot maybe 100 200gr hc LS loads at 1230fps and 2-3 hundred 135 noslers at 1500fps. My gun looks just like yours. The last half of all my shooting has been with a 20lbs spring. Even with my hotter loads the ejection was never crazy far. I'm very interested it what becomes of your investigation. Please keep us posted.
  12. I just checked my G20SF frame, and it also looks pretty similar to yours. This frame was designed for the 10mm, so I can't imagine it not being able to stand up to that 9.0gr load. Like I said, even at Hodgdon's listed 9.5gr max, it's rated @ 34,600psi (2900psi below SAAMI max).

    Anyone that has a G20SF & reads this thread, post a pic of the inside of your frame. List your round count, types of loads & recoil spring rate. That should give us an even better idea of whether this is normal or not.

    #12 Meathead9, Apr 2, 2012
    Last edited: Apr 2, 2012
  13. Good point meathead. My brother got a g20 the same time I did. But his has half the round count and almost no hot stuff through it. Tonight I'll see if I can run up to his house and check it out.
  14. Thanks guys, sounds like with some of your round counts, maybe it won't progress much from here. I might back down to 8.5 gr LS/180 XTP for my plinking load and use the 9.5 LS/180 XTP for carry on the rivers.

    I wanted to get the BTB 200 WFNGC close to 1200, but I am skeptical of more workups, and more stress in that area.

    I am as follows with the 200HC

    1140fps 10 shot avaerage
    8.2 LS book max, have only shot 10 of these
    New starline
    1.250 oal

    1160 fps 5 shot average
    8.4 LS .2 over max no signs, have only shot 5 of these
    New starline
    1.250 oal

    I'll be curious to see what you find orange!

    #14 AstraPat, Apr 2, 2012
    Last edited: Apr 3, 2012
  15. Just looked at my SF lower and I see some light battering in that area too, but no cracking or mushrooming. I have run primarily, good factory loads and a few decent handloads but nothing nuclear. pretty much all around 180gr @ 1150fps kind of stuff or 200 at 1100fps. On this frame I'd estimate 300-400 rounds.

    Might just be that the slide speed is a bit much and it may need a heavier spring. I'll have to watch this area after I get the slide back and run the compensator.

    I'll bet it'd only take a very few hot rounds with a too weak spring to cause that kind of damage. It doesnt look like it's effecting the slide rails yet, but I'd watch for weird wear patterns id you continue to shoot it hot.
    #15 Ethereal Killer, Apr 2, 2012
    Last edited: Apr 2, 2012
  16. Well pat I just took a look at brothers gun. Its in about the same shape as your, (mines a little worse) his gun has 1500 to 2500 powder puff rnds through it. Maybe just a handful of 135's at 1500 fps. Either this this is completely normal, or we've all got a big problem on our hands. I'd love to hear what glock has to say. If I can figure out how to post pics I'll put some up. Aaron
  17. I wonder if this is just related to the sf frame? My gen 2 g20 has stock 17lb spring and all I shoot is 180xtps with 9.8g of 800x. Just inspected my frame and looks as good as new. Is the 9.0LS have a higher pressure than 9.8 of 800x?
  18. Interesting! I agree with the high slide speed, depending on load/spring weight ect.. although, (not bashing the design) I don't feel there is a lot of surface area to start with in this contact area. I also have a G27 & G30, and with the frame/slide design on guns using dual RSA's, there appears to be a lot more slide to frame contact area to spread out the dissipating energy.

    Add the potential power of this cartridge, depending on what ammo is being shot, slide speed, and round counts, and you get a certain unknown stress x cycles. The faster the slide is traveling rearward, the faster the slide has to stop before it starts returning forward.

    I am deff no expert though.

    I am going to give Glock a shout soon. I wonder, giving ones steady diet of a certain load, if it will progress further and get worse? Or it will continue to look like this after the next 500-1k rounds?

    Pics would be great!

    Not sure! I have never seen the inside of a Gen2 G20. Can you tell from my pics if your Gen2 has more meat/polymer/slide to frame contact area?

    As MeatHead stated, according to the 2010 Hogdon reloading manual...

    Starting load
    8.5 of longshot, 180gr SEI JHC, 1.260 OAL load is 31,000 PSI

    Max load
    9.5 of longshot, 180gr SEI JHC, 1.260 OAL load is 34,600 PSI

    So my 9.0 load is somewhere in between. Not sure where, as I doubt the pressure curve is linier
    #18 AstraPat, Apr 3, 2012
    Last edited: Apr 3, 2012
  19. Yeh, I don't feel a "ton" of recoil when shooting the 9.0 load either. Maybe I am just used to my 27 or something. Would you mind posting a pic of yours MH?
  20. Thanks pat for bringing this to everyone's attention, if glock doesn't get back to you soon I think I'll start calling. These guns should take a steady diet of 180's at 1250fps for 20-30 thousand rounds. 9mm guns have gone 100 thou. Rounds without looking like this. Like a said before, my brothers gun has been babied since day one. And is looking just like your gun. 2000 rounds of powder puff rnds shouldn't be the life span of a g20. And if the frame is damaged then glock should be shipping guns with 22 lbs springs. By the way, my brothers run the stock RSA from day one. Aaron

Share This Page