If you have access to a chronograph, and some bona fide 7.62 NATO ammunition, clock a few rounds, and using a suitable powder in the 4895 range or 748 range, starting at start load, increase in .4 grain increments until you have matched the velocity. You should be OK.
Of course, keep an eye on your pressure signs as you would, but if you find a suitable load to duplicate the .mil velocities you should be right where you need to be.
Also, and you probably already know this, if you are using military style sporting rifles, it is a good idea to FL resize your cases. Some guys will set headspace for minimal setback, and obtain more reuses of their cases.