So having gone through pretty much all three possible mounting options that come with the X300, none give a solid fit on the X-carry frame of my Vtac.

I managed to use the springloaded "P" bracket and got a nice solid interface on a full-size frame I have as well as a compact frame, but it still isn't really solid on the X-carry frame.

The "universal" mount that ships on the light was sloppy with everything but the rail on my 1911 Tacops and the "rail lock" option was decent on the other frames, but still no dice with the X-carry.

Anyone have any experience with this light and frame combo? If nothing else, I'll just mate the Vtac to the FS frame and be done, but I'm trying to get used to the X-carry frame.

Not to try to talk you out of your quest, but I am curious why you are concerned about a “solid” mount and what it will do for you.

Virtually all of my near-weekly practice sessions include shooting with a P226 or P320 that usually has a light mounted. Because I don’t like subjecting a real light (X200 or X300) to the stresses of that much shooting (and because I don’t like cleaning the lens or covering it with electrical tape every time), I use a dummy light. The dummy light is definitely not a tight fit and rattles like a 1973 Jimmy when I shake the gun, but I never notice the fact when shooting.

You should get the X300U with the T-slot mounting rail instead of the Rail-Lock mount.

You'll need a screwdriver to remove the like, but it's on tight, like a tick on a dog.

So I have a x300u mounted on my P320 VTAC, honestly not sure how the hell I got it on there, but it’s rock solid. So much so that’d I’d go as far as to say it’s stuck and I can’t get it off.

I'm assuming OP is using the X300U-A. Would the X300U-B be a better solution?