So here's the deal... Im looking for a side arm to go with my hunting handgun (CVA rechambered to 444 Marlin). I am going to get a GP100 Match champion. But I do not know if I want the 357 or the new 10mm that was just released.

As of today I do not reload and ammo from Midway is about the same price either way 38/357 vs 40/10mm. So ammo cost is not a deciding factor for me.

From http://www.ballistics101.com on paper hot 10mm and hot 357 are only 10-30 FPS difference on muzzle velocity for same weight bullets.

Like I said im set on the GP 100 Match Champion so I dont want a glock or 1911 or any other option. Just dont know which caliber to get in this one. (unfortunately both is not an option)

Intended purpose:
Hunting/Hunting side arm
Woods bumming
Occasional carry

Lets hear it...

Mitch

Not I have a strong opinion either way but here's my experience.

I was shooting the Buffalo barnes 155gn 10mm load at 1550 with a 6" G40 with aftermarket barrel. (matches or slightly higher then factory listed velocity)

I have a GP100 6" and am shooting the 140gn buffalo barnes load which is suggested to be 1518 fps with a S&W 5.5" barrel but i haven't chronoed it yet.

Bullet weights aren't the same, but I suspect the cylinder gap would narrow any performance/energy difference between the two on
the the same platform.

For hunting use, I might lean towards the 10mm due to a slightly larger bullet diameter which translates to slightly larger expanded diameter but differences are minimal.

Since you placed hunting first, I would go with the 10mm. While the energy may be the same, the 10mm is larger diameter so will have the edge for hunting in my opinion. Buffalo Bore has some great loads, all the way up to 220 gr at 1200 fps.

To be honest though, I would go with the 5" 44 Special GP 100 as my choice. You give up a round but for hunting and woods bumming I love the 44 Special