I have several .30-06 rifles, including a Winchester M670 carbine with a 20" barrel. Shoots the same loads as my other .30-06's. Gets about 50-75 fps less than 22" tubes, and 75-100fps less than 24" tubes. The carbine really loves Ramshot Big Game with 150 gr bullets. My other '06 rifles like Big Game with 150 gr bullets.
Your mileage may vary......
