No......... Not a stock 17 barrel on a 19 frame, or a 22 barrel on a 23 frame. & a few other combos. Only factory interchangeable barrels are .40 S&W to .357 sig and vice versa. You can also run a 23 barrel in a 27 frame, and a 19 in a 26 frame, but I do not think the factory signs off on that.
it is not just the barrel length that is larger. If you try putting them together, go looking for a Glock Armorer to get them back apart again. It all fits till you put the slide on the frame. Then you see everything is locked up, and the gun will no longer field strip. If you are at that point before you read this, PM me, and I can advise you on disassembly.
I cannot really understand why one shoud mess about like that with his GLOCK!
For God sake why don't you get a G17 and save yourself all those problems?
Then it's true that the barrel will protrude and you won't be able to field strip your gun.
I have a gen4 g20, bought a 6" barrel & it shoots great! Sticks out the barrel pretty good but functions perfectly. I also have a gen4 g21 & swap the oem 4" g20 barrel into it & it preforms wonderfully. I've also placed the 6" g20 barrel in my g21 & it also preformed flawlessly. Nice thing is i can carry 2 10mm glocks if I want. The only thing I did was get a heavier spring for 10mm barrel to use in the g21, same weight spring that's used in the g20. Every configuration works flawlessly! So now I'm on the hunt for an extended barrel for my gen3 g19 & wondering if a oem gen3 g17 barrel will work or if I should just get an aftermarket extended g19 barrel. 5" would be nice, also a threaded barrel...
The Gen3 17 barrel lugs are spaced differently than the 19 lugs are, so they cannot be swapped. If you want a longer barrel on your 19 it would have to be an aftermarket barrel. A G19 factory threaded barrel is an option though.