RE: 30/30 For Elk
Velocity (fps)/Energy (ft/lb) Trajectory Tables
muzzle 100 yds 200 yds 300 yds muzzle 100 yds 200 yds 300 yds
30-30 Win. 160gr. 2400/2046 2150/1643 1916/1304 1699/1025 -1.7 3.0 0.2 -12.1
With the LR ammo from Hornady the same caliber bullet you shoot from your 30-06 is only 300fps slower. As long as you keep your shots on elk inside a few hundred yards (where 95% of all game is shot anyway) I think the 30-30 would be just fine. According to the chart you're still past the recommended 1500 ft/energy to 300 yards.
I've been thinking of picking up a used 30-30 for this very reason, although I still love my 7mm RM too. Just something nice about a 30-30 strapped in the scabbard while riding throught the sage brush were I live.