Greetings. I just got my second Dagger upper today. I got it for my SCT19 frame. I cannot slide it onto the frame without depressing the takedown lever. Once on, it appears to sit flush and normal. It racks back normally, but gets stuck when released. I immediately thought, oh no - I got a messed up slide, and tried it on my dagger frame. It went right on like butter and operated normally. My other dagger slide will go right onto the SCT frame and function like it’s meant for it. But this new one I got doesn’t seem to want to play nicely with it.
I found a sub where a guy was describing the exact issue I’m having, and a PSA guy commented “tolerance stacking, as long as it goes on and sits flush it’s fine”. Okay, lol, well I’m not sure having to smack the slide forward every time it’s racked back is fine, but I’m no expert. Hopefully that’s not the answer support gives me, as I’ve already reached out to them.
Wondering if ya’ll have any ideas.
There is no guarantee that one manufacturers part will work with another manufacturers part. They are both “based” on the Glock but there can be differences in manufacturing and tolerances. Who knows, could be as simple as changing the slide release for a Glock or PSA release, or that could just be chasing a red herring. Can you live with just switching the slides since they seem to work that way?
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Yeah, I can live with that. I got that specific color for that frame but it’s whatever. I also have a slide release coming just to try it.
yeah, I was wondering if it was a specific color or type that you wanted. The thing is, if you ordered another slide, it might fit just right… but then you’d have to get another frame… it’s a vicious cycle! 
Thats gotta be it, lol. An odd number thing. 1st one works fine so 3rd one should too
Tolerance stacking is a real thing…anytime you mix parts from multiple manufacturers (not just with handguns also) you run the risk.
Have you tried swapping the barrels and keeping the slides to the intended frames?
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Yes sir, and that’s what I’ve narrowed it down to. My other dagger barrel with the new slide works perfectly fine with the sct frame. So something about the new barrel doesn’t like the frame.
I say if you swap the barrels and both run, keep em that way; unless there’s some aesthetic design you have for keeping the slides and barrels together as they came.
For now I’ve just swapped the entire slides around. My new one is gray with a black barrel and my other one is black with a chameleon barrel. I didn’t like the rainbow with the gray lol.
I’m glad I read this because I was thinking about going a cheaper route for a complete, yet reliable, upper for either a GritGrips or SCT19 build. I think I’ll just get the Shadow Systems G19.3 complete upper & add a Radian & NDZ captured recoil assembly. At least I know the Shadow Systems slide fits both frames without issues. Or, at least I’ve seen/read as much on the GlockMod & Polymer80 Reddit subs.