.30 AK upper for the AR is well worth

the asking price. It lets you practice for 7c a shot, as vs 12c a shot, and there's steel cored .30 ak ammo and bullets, for when you want to shoot up propane tanks, transformers, pipelines, etc. Also, it can use the 174 gr hbt match ammo, at 1050 fps, for 400 ft lbs, and no sonic crack, thru a suppressor. The AR's barrel is easily removed for threading, and after the AWB sunsets, such barrels will naturally come with threads at the muzzle. Such a bullet has a very high BC, so it will still have 850 fps remaining at 200yds. While the velocity is not exactly "high", it is retained so well that such a load permits quiet head shots on sentries, to 150m, and it also of course pierces at least some makes of level II concealable body armor.

the .311" bullet can be had in a 150 gr softpoint, too, for taking deer more effectively than can be done with .223. All in all, I regard the .30 AK upper for the AR to make more sense than one in .300Whisper.