If hunting in Colorado and maintaining possession of your rifle, pickup and other gear is a goal of yours, I'd suggest keeping with the 1,000 ft/lbs at 100 yards. Otherwise, you are a POACHER.
1. CENTERFIRE RIFLES
a.
Must be min. .24 caliber (6 mm).
b.
Must have min. a 16-inch barrel and be at least 26 inches long.
c.
If semiautomatic, they can hold max. of 6 rounds in the magazine and
chamber combined.
d.
Must use expanding bullets that weigh min. 70 grains for deer, pronghorn
and bear, 85 grains for elk and moose, and have an impact energy (at
100 yds.) of 1,000-ft. pounds as rated by manufacturer.
e.
It is illegal to hunt game birds, small game mammals or furbearers with
a centerfire rifle larger than .23 caliber during regular rifle deer and elk seasons
Wof I-25, without an unfilled deer or elk license for the season.