I know most people on this site are bowhunters but next fall i'll be going elk hunting with my gun. My question is...what size gun should i get?
300 Win Mag
308 win
Any other advice?

They will both do the job but id personally get the winmag. and practice alot so your confident with the gun and your shooting because you never knw when your shot could be at 250yds. or 20yds so just practice alot at alot of distance till your confident in the gun and you ability

Do you have a rifle now? If so what is it chambered in?

All of these are fine elk calibers.

.270 win or mags, 7mm-08, .308, .280 Rem., .284 Win., 30-06, any of the 7mm mags, any of the 300 mags, 8mm Rem mag., .338-06, any of the .338 mags, 35 whelen, 350 Rem mag., on up to as big as you want.

If you have any of these listed you already have a good elk rifle.

One of the .300 Mags. Good luck.

I second the vote for one of the 300's!

The 308 with it's small case does not drive the larger .308 bullets (180gr and up) as well as some others....

30-06 is a fine place to start, 300WinMag is lovely, 338WinMag even better....

IMHO, more is better depending on your ability to:

(1) Afford it,
(2) Get your rifle set up PROPERLY, and
(3) Handle it.

[Many cartridge myths likely to follow.]

EKM

I'd go with a 30-06 or a .35 Whelen. Both are excellent big game cartridges with good bullets.

I own a .300 Win Mag, and it is my primary Elk gun. Recoil isn't much stiffer than an '06, and it is easy to shoot well. I prefer the 165 or 180gr Winchester Fail Safe loads. Elk are BIG and TOUGH! The Fail Safe will out penetrate virtually any other bullet out there, and penetration is critical on Elk. The Fail Safe will smash through heavy bone and tissue and still retain almost 100% of it's original weight. I know this is not what your main question, but I think that too many hunters think just because they are shooting a caliber suitable for Elk, that bullet choice is of little importance...NOT TRUE!! Every animal I have shot with the Fail Safe's including Elk have been clean one shot kills. Where are you going to be hunting?

u dont need all the power people are talking about ... .270 win is PLENNTY for elk ... .257 Weathby is good.tired of all these omg 338 mag i great **** that

270, 30-06,308, 7x57, 280, 7mm Mag or STW one of the 3900 mags. All will work if you do your part. All have killed many an elk and bigger game. The obsolete 8 MM Rem Mag was a good one as well. I used a 338 for several years and itwhile it did the job, I was never impressed with it. Finally sold my last one a few years back. It wouldn't do much that the 300 mag would not do.