Can anyone help me identify factory .357 mag ammo that meets Colorado hunting regulations of 550-ft lbs of energy at 50 yards. I know Federal 180 grain castcore meets this requirment are there others?

What is the length of your barrel? In order to compute energy, one must know the muzzle velocity. You might make 550 lb-ft at 50 yards with an 8-3/8 bbl, but the same load may make less energy out of a 2 inch snubbie.

Colorado DOW requires a min 4in barrel

You can check the manufactors ballistics tables for velocity and energy specs. ( Federal, Winchester,Remington, ect. ) It will give you the numbers from the muzzle and set distances.
I think your gonna find very few hunting loads are going to meet this requirment.
Most 357 mag. loads from the factory are in the area of 1200fps. With a 158 gr. bullet. If your able to handload, you can get real close to 1600fps using the right powder.
{as velocity goes up so does energy}
Reloading manuals also have ballistic tables that can help guide you.

I've mentioned this in another forum where you posted the same question but...

Reading the CO DoW regs on handguns I believe they are talking only about handguns used as the PRIMARY hunting tool. If you are hunting with a rifle and carrying a handgun as a backup/camp gun I don't think it needs to meet that minimum of 550 ftlbs at 50 yds. I'd check before trying to pump up my .357 Mag to meet it.

If you are talking about using the handgun as the primary hunting tool then I'd say step up to a bigger cartridge. A good excuse for a new gun!

Yes , the 357mag with 158gr and 180gr bullets can SAFTLY meet the requirment.
It can do this below the max loads.
Powders like W296, H110, and LIL'GUN will be needed.


I agree with pumpkinslinger on the use of a larger gun. I'd be using my 44 mag. with the 300 gr XTP, But thats not what the question was about.