Not a huge fan of the cartridge, but at basically .30-30 Win power certainly useful.
Had an old Colt Sporter in 7.62x39 that was used by a few kids to kill their first deer. Always used the Federal Red/white box 123 soft points.
Years back I had the opportunity to snag a mess of 5.45 x 39 7n6 Russian ammo for a song, so bought it all. Then when the AK74's finally arrived I was set.
Being an AR guy at heart I was one of the first who bought one of the LWRC 5.45 piston uppers several years back when they did a small run of them. With ACS mags mine runs pretty close to flawlessly. At a nickel a round I still have several thousand rds of ammo left.
FN in MT