I had two Zastava models. Bought one from a friend that had two that he stuck in the McMillan mauser stock. He sold me the 243 but kept his 375 H and H which he has never fired. (must be nice)
The other I found in a gunshop with a McMillan stock for $300. It was a 25-06.

I rebarreled the 243 to a 7-08, got bored and had it re-reamed to 284 win, got bored again and had the bolt face opened up and made it a 7 rem mag. Now a good friend has it. The magazine had a small pc of steel making it shorter for the 243. It was easily altered. A longer mauser follower completed the change.

The finder rifle got shot out and was also turned into a magnum. It became a 375 Taylor and it will never leave my posession.

I'd buy that used Mark X and then have fun. When the barrel gets tired then the real fun can begin. FYI that Mickey stock suits the Mark X well and fits the shooter as well.

Hope you get it.