Glock 40 upper on Glock 20 frame

So I found the compatibility list for everything BUT the Glock 40.

Anyone have these two and can confirm interchangeability? I wanna use the Glock 40 upper on my Glock 20 frame.

And for the record here is the compatibility list for reference.

Receiver------------Upper/s
G17…G17,17L,34
G17L…G17,17L,34
G19…G19
G20…G20,G21
G21…G20,21
G22…G17*,17L*,22,24,31,34*,35
G23…G19*,23,32
G24…G17*,17L*,22,24,31,34*,35
G26…G26,27*,33*
G27…G26*,27,33
G29…G29,30*
G30…G29*,G30
G31…G17*,17L*,22,24,31,34*,35
G32…G19*,23,32
G33…G26*,27,33
G34…G17,17L,34
G35…G17*,17L*,22,24,31,34*,35

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bet you can do it, give it a go, do a review

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Can I borrow some money in case it doesn’t work?!?!

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Hell yeah you can,

@Belt-Fed you’re up!

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Someone could donate me one. I’d be obliged.

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Wait…what??

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James needs some of that gun of the month money you been hording

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LOL, guess I give ya’ll the wrong address. :rage:

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Ok so back in topic. Does anyone have both that can run a test for me please? The internet is unreliable.

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Only glock I have is a 19, so I am useless for you.

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I don’t though would like one, the 10 and 45 seem to be interchangeable across the board with respect to frames/slides I’d bet the is no different

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I almost guarantee that this will not work, but I have both and fan try it.
The reason I say this is because the 40 width is the same as the 9mm width “slide”. The 10mm slide and the 45 slide should be the same as @Robert already stated. Let me go grab them and see and take some pictures for you all. One minute.

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Okay so here is what I have a Glock model 22 “40cal” and a model 40 “10mm”



Obviously there is a difference in length and width of the slides

The slide inner rail width Has a difference of 0.002” no big deal.



Funny enough the slide of the 40cal does fit the 10mm lower. Of course there is a length issue.

Now this still wouldn’t work very good, note the offset of the ejectors.

Now some of the difference could be because of the gen 2 vs the gen 4 or the long slide vs the standard slide.
If you want to shoot 40cal out of your 10mm Glock technicality you can just load your 10mm with 40cal rounds at your own risk. I know a few people that do this. I don’t recommend it but I know it has been done.
I hope this helps @Chuparosa

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I believe we were discussing the model 40, not a 40 cal, if not then I’ll find a corner,

also, those are high quality photos that load slow, can you select 50% in the preview window when you post, I think it helps

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… well that’s my fault. Yeah I’m sorry @Chuparosa I miss read that. Thank you @Robert for helping me pull my head out of my democrat!

@Chuparosa it might work. Honestly I would get a model 20SF if at all possible.

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I’m on my phone. I don’t think I can select that but I will check.

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I did those already, if there is no preview window then I doubt you can

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You are correct, though this is good info since I do want to shoot .40 SW out of it. :slight_smile: Lonewolf and KKM may make .40 SW barrels to fit a G20.

If I ever get another Glock it just might be either a 29 or 20SF.

I wanted to be able to use the longer slide / barrel from the Glock 40 and that’s where I’m having trouble. I think it’ll work if they are both Gen4’s…

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Lone Wolf generally does have conversion barrels to switch the 10mm Glocks to .40S&W, but what’s in stock can vary, and they have discontinued some things to adjust to the current market.

I think the G40 slide assembly will fit on a G20 frame, but I don’t have them to try it. I’m limited to the Polymer80 PF45 that I built with a longer 10mm barrel and slide from Lone Wolf. You might look at what barrels and slides they have, and consider them as an alternative to buying a G40 slide assembly.

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I did check Lonewolf and they don’t have anything for the G20. But I’ll email them and KKM (who did my 9x25 barrel) to see if they can one off me something.

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