There is not one
There is no SAMMI spec. for +P 9mm Makarov.
I would also be a little concerned about shooting hot ammo in a PA-63. The Aluminum frame of those pistols does not like abuse.
I agree, the PA-63 carries quite well. Lots of folks put a grip sleeve on them, they will make the web of your hand sore after an extended range session.
The PA-63 used to be among the least expensive pistols on the market. They are still pretty cheap. For years they were the hundred dollar handgun, or less. I paid 89 bucks for mine out of the old shotgun news. Allegedly used by the E. German STASI. and surplused.
I have always liked mine, lightweight, accurate, and mine has a nice polish and blue on the slide. I did have to replace the recoil spring, after about ten years of ownership.