I have two P320 Professional pistols, one is the full model and the other is the carry model. If I bought a threaded barrel for the full sized, can it used it in the carry, also?

Would the can being farther away from the slide cause an issue?

It will be interesting to see what others say.
Being curious, I tried a full size 9mm barrel in both a Carry and an XCompact slide, and it fit in both with no problem. When I put the XCompact slide and full size barrel on the receiver, though, that combination was not happy. After I pulled the slide back to the lock position, it wouldn’t move forward again with the slide catch depressed. Only by pressing up on the barrel did the slide release to allow it to be removed (whew!).

In view of that I decided not to try it with the Carry slide even though that slide is closer in length to the full size.

I don’t know what caused the lockup with the XCompact slide, whether anything similar would occur with the Carry slide, and it may just have been some sort of no-repeat fluke.

Thanks for sharing your experience sigfreund. I don't want to risk screwing up my Carry pistol, so I'll get a second barrel for it.

Sigfreund--compare the locking lugs on the compact to the full size. I think the full size will be slightly longer in height--getting hung up on the slide bar.

Well, curiosity overcame caution, and I tried the full size barrel in a Carry slide.

At first it seemed that there would be no problem using the FS barrel in the shorter slide. The slide cycled by hand normally a few times and then I tried running a stack of dummy rounds through the action. Again the first three rounds cycled normally, but then the slide again locked back without any pressure on the slide catch lever. I had to push up on the front of the barrel to release the slide, and that’s as far as I went with my experiment.

As suggested I did measure parts of the three barrels.

I measured the diameter of the tubes and widths of the barrel hoods of the FS and XCarry and they were identical according to my dial calipers. There was a difference in the measurements from the top of the barrel hood to the bottom of the barrel lugs or locking lugs*.
FS: 1.085"
Carry: 1.100"
XCompact: 1.175"

I don’t know how those differences could affect what I experienced, and I don’t know why the full size barrel won’t work properly in the shorter slides. It may just be some dimensional difference that I didn’t find that allows it to get jammed at an enough of an angle to lock the slide back. It could be that a different FS barrel would work fine, but I have ready access to only the one, and I don’t want to risk something that I can’t correct by wiggling the barrel.

* Whatever that feature is called.