Over at the AR-15 discussion area, under ammunition, they listed the top performing loads in various calibers. The 125gr Lapua Mega spire point was listed as the top choice in 7.62x39.
The Lapua 125 gr JSP proves to offer outstanding terminal performance!
Out of a 16” barrel:
Bare Gelatin: vel=2316 f/s, pen=17.3”, RD=.62”, RL=.43”, RW=122.6 gr
Car Windshield: vel=2323 f/s, pen=14.8”, RD=.60”, RL=.40”, RW=110.6 gr
Performance is similar to the Trophy Bonded Bear Claw bonded JSP bullets used in the Federal Tactical loads, with deep penetration, excellent expansion, and good weight retention. Because of the larger permanent cavity and greater bullet mass, the Lapua 125 gr JSP will offer somewhat better performance than the .223 bonded JSP’s. This load will be a good choice for LE use against car windows and should also be outstanding for hunting deer and other similar size game.
I haven't tried this ammo yet, but it seems promising. I might try it out this year on Whitetails.