the reason it works the other way round in the tokarev is that the 9mm round is shorter ( of course) than the 7.62x25- my tok came with both the 9mm and 7.62x25 barrels-was built on the 7.62 frame and uses 7.62 mags, which some people have found unrelaible, although i haven't found that and i've been using 9mm since i got the gun- the "new" conversion uses a SPACER at the rear to take up the extra space in the mag- your mag well may not be long enough to accomodate the longer round, and the longer ( front to back) mag
9mm is one of the cheapest rounds you can get, so it may not be worth the extra expense unless you have ready access to the russian stuff-