Storm Lake 21 to 10MM Conversion

Discussion in 'Glock Forum' started by sparky80, Jan 12, 2014.

  1. sparky80

    sparky80 New Member

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    Been looking at one for awhile but, different sources online claim different things. Some say you need a extractor change and spring change, some say only one or the other. Other places say just swap the barrel. So does anyone have one?
     
  2. scubadvr

    scubadvr New Member

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    What Gen Glock to you have? I emailed glockmeister and asked them what would be needed for my Gen 4. They said just barrel and mags.
     

  3. gunny91

    gunny91 New Member

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    A glock 21 is a 40 cal ant it?

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  4. sparky80

    sparky80 New Member

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    I have a Gen 4 21. 21 is 45 ACP. Thanks
     
  5. gunny91

    gunny91 New Member

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    I never got into flocks so I don't know what is what but I used to work at storm lake barrels as a machinist

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  6. gunny91

    gunny91 New Member

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    But for what ur asking u can just switch out barrels its no different then getting a 9mm conversion barrel for a 40 cal

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  7. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    That's a new conversion to me. I am not sure how the .45 extractor/ejector will perform w/ 10mm
     
  8. SSGN_Doc

    SSGN_Doc Well-Known Member

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    A .45 has a bigger breech face. Not sure how well it would work without a whole top end.
     
  9. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The difference between .40 and 9mm is quite small compared to the difference betwen .45 and 10mm/.40
     
  10. gunny91

    gunny91 New Member

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    It will be sloppy but it will still perform

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  11. gunny91

    gunny91 New Member

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    There is a .05 thousandth difference in casing diameter between a 40 and a 45 so it actually a smaller difference in those then a 9mm to a 40

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  12. SSGN_Doc

    SSGN_Doc Well-Known Member

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    The rim diameters are:

    9mm is 0.394
    .40 is 0.42
    10mm 0.425
    .45 is 0.480

    Using bore diameter can be deceptive, because the 9mm is a tapered case. The difference may not be enough to harm reliable extraction, but that would be my concern based on breech face dimensions already possibly being a bit generous.

    I would also think a stiffer recoil spring may be needed for the 10mm since it is a higher pressure round.
     
    Last edited: Jan 14, 2014
  13. gunny91

    gunny91 New Member

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    I assure u it will run were talking about a glock there built to run anytime anywhere

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  14. SSGN_Doc

    SSGN_Doc Well-Known Member

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    Oh I don't doubt that it will run, just wondering about how optimally it will run. It might be prudent to have a bit more extractor engagement for reliable extraction under adverse conditions when the breech face may get a bit messy, or there is a failure to fire due to a bad primer.

    Just pointing out that if one can afford a whole upper half, it may be a better option in the long run.
     
  15. gunny91

    gunny91 New Member

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    I always thought the conversion barrel was a sketchy idea ...yea it works but like u said if a man had the money just get another slide

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  16. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The 10mm is a high pressure round (in many loadings). With the reputation Glock already has for case failure with the unsupported chamber, do you think it is a good idea to leave that much more area unsupported?

    The 9mm and .40 shell plates for reloading are almost interchangeble. That is how close the base diameter is. Try resizing a 10mm (or 40) case in a .45 shell plate. You will rip the head off more often than not.

    Storm Lake and some people may tell you it will work, but I prefer to use the appropriate slide for that job. I have a G-20 and plan on getting a .45 slide to ad to the versatility of the gun. I already have .40, .357 Sig and 9mm conversion barrels for it. They work. The 9mm uses a lighter 10 lb recoil spring because of the slide mass.
     
  17. sparky80

    sparky80 New Member

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    Thanks for the replies. I guess I'll start looking around for a used 20, Gun show this weekend. We'll see what turns up.