KB! In New G20. Ideas? What Next?

Discussion in 'Reloading' started by pasky2112, Aug 29, 2012.

  1. According to Hornady 8th Ed., the gun was a Colt Delta Elite with a 5", 1 in 16" twist barrel using a Hornady case and Winchester WLP primer.

    The Glock barrel is 4.61" - not a lot of difference but still, the muzzle velocities would be lower with the Glock.


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  2. Can you post the complete data?

  3. pasky2112

    pasky2112 Senior Member

    Yeah! Those are the best! That way I can reload it with more powder b/c there is more case volume!!

    dkf, You're joking, right?

    I'll take some pics of the brass and we'll play a little game...no tricks.

    Also, I'll post the book data I used for those that don't have the Hornady 7th 10mm auto 180 JHP AA#7 data.
  4. dkf


    Pipe down scooter. That was posted up in general glocking some time ago. If memory serves me right it was one of the Swamp Fox loadings at the Max that was shot in a Glock barrel. Those loads were only recommended to be shot in a more supported tighter barrel like a KKM.
  5. pasky2112

    pasky2112 Senior Member

    I actually have a keg of PP and it's one of my fave's in .40's. I also like AA#5. So when I purchased BD for 10mm, I threw in some other powders I wanted to try while I was paying hazmat. So I got a pound of AA#7, Win231 (for .40 also) and CCI #300's. As much as I liked AA#5 for the .40, the data for AA#7 looked like it'd be a good choice for both .40 and 10mm. Prior to the KB, I loaded and shot almost the whole pound of AA#7 and had no chrono walls, unusually bulged brass for a glock stk bbl...any more than you'd see in factory loads. The only thing notable was that I read from multiple resources was that they saw flattened primers with only warm loads using AA#7. I saw the same thing in my starting mid-range loads. So, Against my better judgement, I noted them but didn't see anything else at the time I thought was a 'red flag' to stop. So, FWIW.... I agree w/ you 100% about PP. And i will use it for 10mm and, of course, .40's.
  6. Power Pistol is a lot Flashier then AA#7. #7 takes a lot more grs of powder to have the same velocity as PP. They both fill the case pretty well. I would not use PP inside. Way to loud and too much flash. BUT, I hate how fast #7 disappears as I am loading with it compared to PP. BOTH have the same max velocity in my analysis of load book data and then testing it over a chrono. Even if you find a source that says one is better then the other it's just not a big enough difference to worry about. Other powders are better for getting max velocity out of 10mm. 1150fps is no joke in a G20 and that is where I stopped. Anything much past that you are pushing the limits. As evidence by your KB at 1250fps.
  7. pasky2112

    pasky2112 Senior Member

    I thought it was funny... but I still want to show what my brass looks like b/c i think didn't make it clear of what I meant by 'usual glock bulge'.

    - Scooter :)
  8. Doesn't Glock's polygonal rifling lead to higher velocities for a given barrel length?
  9. That's a good point! I have no idea. I wonder if there is a pressure difference for a given load in a Glock barrel versus, say, the Colt Delta Elite that Hornady used to test the load.

    That might be another reason to stay with mid-range loads.

  10. dkf


    Post up some pics, I like pics.:wavey:

    That sign off made me.:rofl::supergrin:
  11. Read the original post. I edited to the important points.


    1) He was trying to get 1200fps and he got 1250fps in a shorter barrel gun.
    2) Known good factory ammo with a much lighter bullet (155gr) only does 1300fps in his gun.
    3) Guns really vary. You need to get a safe baseline as to what you can expect and not try and cross that threshold no mater what the data says "you should get".

    I would be willing to work up a load using the exact components in the manual to max. But when you are mixing and matching primers, brass and bullets you need to be conservative. Not just shoot for a velocity because the book said you can do it.
  12. Test Conditions:
    Handgun: Colt Delta Elite
    Barrel: 5", 1 in 16" twist
    Case: Hornady
    Primer: Winchester WLP
    Bullet Diameter: 0.400"
    Maximum C.O.L: 1.260"
    Max. Case Length: 0.992"
    Case Trim Length: 0.987"

    Bullet: HP-XTP
    C.O.L: 1.260"
    Powder: AA-7
    9.3 gr -> 950 fps MIN
    9.8 gr -> 1000 fps
    10.4 gr -> 1050 fps
    10.9 gr -> 1100 fps
    11.4 gr -> 1150 fps
    12.0 gr -> 1200 fps MAX

    Throughout the range, 0.5 gr (more or less) yields an additional 50 fps. The curve certainly hasn't flattened out.

    Hm... :dunno:

    Any chance the gun fired out of battery?

  13. pasky2112

    pasky2112 Senior Member

    Just for kicks, and to try to show what I saw when looking at cases before the KB, I took a photo comparison of 4 cases shot that day in my G20. 3 are reloads ( one is pretty obvious :whistling: ) and 1 of the grp is a factory load right out of the box.

    L --> R = #1-->#4 Which is which?

    Now tell me glocks don't bulge cases and I'd have to question whether you've ever shot a stk glock bbl b4. (flame guard on)
    To be clear, I'm not trying to be pissy here. Just want to clarify what I meant by 'usual bulge' and what it means in terms of signs of dangerous pressure.

    Attached Files:

  14. Those are expanded not bulged. They will probably drop right in the factory barrel and you can probably spin them in the barrel. Try it.

    If they don't spin they have a little guppie. You can't see it well in the picture. You may see it different because you have held them and see it better and know what to look for in the picture. But to me those look OK except the primers look flat but it's not easy to see.

    That is just how Glock 10mm brass looks. A little barrel shaped.

    BTW, I would guess you had a overcharge. Maybe not a double charge but a overcharge.

    Are you using a Progressive Press?
  15. I think I read the original post, but that info wouldn't indicate that Glock barrels are in fact faster (or slower) - especially with all the other variables. Am I missing something?

    SARDG (Search and Rescue Dog, USCG) ;)
  16. Nope. It just varies.
  17. pasky2112

    pasky2112 Senior Member

    It was the end of my session so the chamber wasn't exactly clean. But I only fired maybe 100 rnds. I always rack a round from mag into chamber and NEVER drop one in manually via locked open slide. I purposefully 'drop' the slide as a habit and never 'ride' it. (pet peave) The remainder of the rnds that were in my mag have unchanged OAL. I mentioned before, I use a Redding Comp Die and i measured ea rnd individually for OAL before accepting it, in this case b/c I was working with max load. I used a Dillon 10mm Case Gage, also.
    So, I guess there's a chance but I wouldn't know unless it was obvious after I racked the slide and looked at it. I typically look to make sure and also look when the slide stop kicks in on empy mag. After the KB, the case was stuck in the chamber and partially OOB. Looking back, I'd guess maybe 1/4"? I was still pretty stunned and was concerned about the pistol damage, at the time...after I checked that I wasn't damaged, of course. ;)
    FWIW, the blown case came out of the chamber pretty easily when i racked the slide.

    This is part of the thing I'm trying to get in my noob head...how can a load go from usual case bulging to blowing without showing other case signs in between from previously fired rnds in the same batch?? I have to conclude that you're not always going to see 'smiles' when you're red-lining. But if you do, stop, obviously.
  18. Maybe... The load was supposed to deliver 1200 fps and we all suspect that load data is optimistic in terms of delivered velocity. So, how come the load actually delivered 1250 fps? To do that, based on the 0.5 gr per 50 fps curve from the Hornady manual, there was at least 12.5 gr of powder in the case. Probably more because the manual probably overstated the velocity in the first place. So, maybe 13.0 gr... Maybe even more if the velocity vs charge curve flattens out after 12.0 gr.

    I'm just guessing... Maybe the type of barrel accounts for the extra velocity. But then, is there more, or less, friction?

    And what happened to the bullets. More specifically, why didn't they hit the target? Shooter error? Sure, that is always possible - especially if I'm driving. But still, all the other rounds hit the target. Why were only these loads off the target?

  19. dkf


    Kinda hard to tell exactly from the pic but the left 3 look like the spent .40 brass I have. Sort of a tiny "bulge" around where the feed ramp is.

    I would say you either had a small over charge or bad piece of brass. Possibly that piece of brass had a defect or improper heat treat from manufacturing.

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