Colorado DOW regs read as follows:

Handguns, provided they have a minimum barrel length of four (4) inches and comply with the following criteria:

a. Use a .24 caliber or larger diameter expanding bullet.

b. Use only a cartridge or load with a rated impact energy of at least 550 ft. pounds at 50 yds. as determined by the manufacturer.


If it's for protection during any hunting season, the sidearm must adhere to these guidlines. The only season in which you cannot have a sidearm in posession is blackpowder unless it is a black powder pistol.

I have been checked before while deer hunting. Not only will the DOW check your sidearm, but they will check your ammo too. If it does not meet reg, you will be ticketed and escorted out of your AO. I carry a Tokarev. 7.62x25. 1600fps at muzzle.

No, a 9mm will not meet regs. No, FMJ's do not meet regs. (per the FT. Collins DOW office).