Quote Originally Posted by whitewalrus View Post
The regulations seemed to have change recently. I always thought it was rated at the muzzle in the past, now it seems that a 300blk from a rifle barely qualifies, and most loads don?t.
From the regulations: (located https://cpw.state.co.us/Documents/Ru...tions/Ch02.pdf )

1. Rifles using center-fire cartridges of .24 caliber or larger, having expanding bullets of at least seventy (70) grains in weight, except for elk and moose where the minimum bullet weight is eighty-five (85) grains, and with a rated impact energy one hundred (100) yards from the muzzle of at least one thousand (1000) foot pounds as determined by the manufacturer's rating, and except for mountain lion where any center-fire rifle using bullets of at least 45 grains and producing at least 400 foot pounds of energy at the muzzle may be used. Provided further that any semiautomatic rifle used shall not hold more than six (6) rounds in the magazine and chamber combined. A fully automatic rifle is prohibited.
6. Handguns, provided they have a minimum barrel length of four (4) inches and comply with the following criteria:
5
a. Except for mountain lion, use a .24 caliber or larger diameter expanding bullet with a rated impact energy of at least 550 ft. pounds at 50 yards as determined by the manufacturer.
b. For mountain lion only, use a centerfire handgun using bullets of at least 45 grains and producing at least 400 foot pounds of energy at the muzzle, as determined by the manufacturer.
Those regulations are pretty old. At least a couple of decades.