Anyone have a drawing of the barrel tennon on a Mark X Mini Mauser? This one is marked "Made In Yugoslavia"

I do. I'll dig it up when I go out to the shop.

Good news that you're looking for the right dimensions for the barrel since that means you will not be using the factory barrel. I've never gotten respectable accuracy from a Zastava Mini Mark X barrel in any caliber. But I have a Mini Mark X rebarreled to .221 Fireball with which you can practically strike a match taped to a 100 yard target. Obviously, there's nothing wrong with the little action (although a good replacement trigger helps), but the barrels, in my admittedly limited experience, are disappointing.

I have an early mini that shoots very well.
It seems to be something like 1-11 twist. 60+ grn bullet weights shoot better then 55 grns and below.

I have these numbers for the mini mauser action. 1.5 X 22 MM for the threads. The length is about .694 inch. Maybe someone will have a drawning for these dimensions. I cut this barrel on the chinese mini lathe which can cut the metric threads.

This is from a take off barrel. The 20 degree feature serves as a funnel/loading ramp for a 7.62X39 gun. May or may not be necessary on yours. If needed, just dont make it so big that the web is unsupported. The .090 relief at the end of the threads is not necessary.

Thanks everyone for the helpful replies. Kendog, your drawing is just what I needed, thanks. The rifle I'm working has had the original barrel set back and the job was not a good one, Threads are very wobbly, I did not want to replicate those problems.