What's the ultimate long range rifle cartridge?

[jeff100]

I'm going to build myself the ultimate long range custom rifle one of these days soon.    

With the recent proliferation of new short magnum cartridges, and rifle cartridges in general, excluding the .50 BMG cartridge, what would you consider the 'ultimate' long range cartridge for short action and long action rifles?  Given the performance and success of short fat cartridges for long range shooting (e.g. 6mm PPC), I'm thinking one of the new short action magnums would be the best choice, but I have no experience with any of them, nor do I want to buy a rifle in each caliber to make an assessment.    

What cartridge would you guys pick?  Thanks!

Jeff

[270Shooter]

I'm no expert but I would think a HOT 6.5mm cartridge is the way to go .

And for short actions 6.5-284.

[jeepasaurusrex]

155mm Howitzer 

[jdb]

30/378 or 338/378. JB

[BULLBLASTER]

30/378 or 338/378. JB

[thinkingman]

338 Lapua
408 Chey Tac

[Big10gauge]

The ultimate long range rifle for what? Deer,Bear & Elk?
My first choice would be the 300 WM just because IMO it's a proven long range factory cartridge that's hard to beat. Now if your talking a really custom chamber I would go with one of the necked down 338 or 378 wildcats just like JDB said. Expensive to load and shoot would be the only drawback.

[JoshT]

.338 EDGE... no doubt. Very similar to the .338 Lapua and .338/.378 Roy... but the brass is readily available (.300 RUM). Also, the 300 grain Sierra MK is the projectile of choice for a lot of long range hunters.

[BrushChimp]

I would like to get a .30-378., but the .338 Edge without a doubt has amazing ballistics. I was skeptical at first, but that thing can shoot. .300 RUM brass topped with a .338 shell.

[Bofire]

Long range for an elephant, rabbit, or paper? How far is "long range"? a 16 inch off the Missouri should work.

[high country]

375/50bmg by state arms is the absolute flattest shooting round you will dream up. the big allens, chey tacs, lapua's, wby's and ultra's are your answer.

[bobcat]

I'd just keep it simple and go with the 300 Rem. Ultra Mag.

[Gutpile]

338 lapua. Spelling?

[actionshooter]

.338 EDGE, Shawn Carlock knows his *censored*
.338 Lapua
30-378

for smaller calibers.
6.5-284
For a short action magnum the 7WSM is WAY underated, very good round.

[ICEMAN]

I'd just keep it simple and go with the 300 Rem. Ultra Mag.

x2

Great rifle,....love mine.