Why choose 308?

[Bigeclipse]

I have 308 and 7mm08 deer rifles. The 7mm08 has no advantage over the 308win. This is my opinion so forgive me...
Recoil is the same.
Ballistics are the same.

I don't have a hunting rifle in 6.5CM so I can't compare it to the others. But speculating the recoil is a bit less over the other 2 and ballistics beyond 400 yards are better.

For big game hunting the 308win is more versatile than the 6.5cm. At the cost of more recoil.

If you want to hunt deer beyond 400 yards then the 6.5cm would be the best option out of these 3 cartridges.

could not disagree more. You obviously either do not have the same rifle in 308 versus 7mm08 (same weight rifle same stock etc.) or you do not shoot the same ballistically matched weights in their respective calibers to say they recoil the same. To get the same terminal ballistics and flight characteristics in the 308, you will need to shoot a 165-175grain bullet compared to the 7mm08 popular 140grain. The only way to achieve similar velocities would be a very high charge loading at or above book max and would be a "significant" amount more recoil. That being said, a 308 does not recoil too bad anyways so this becomes a moot point for anyone who is not recoil shy. In my opinion, the 7mm08 wins hands down on medium sized game (deer...maybe an elk) out to 500 yards between the 3 calibers. From 500-650 yards id probably look into the 6.5cm because it will handle wind better than the other 2. You should go join the longrangehunting forum...lots of great info over there.

To the OP...all 3 are great cartridges. As you have stated, the 308 will be the easiest to get ammo at reasonable prices. It will have a wide range of bullet weights to choose from but be careful as the twist of your barrel will dictate which bullets will likely work best beyond 200 yards. The 7mm08 will have less options for ammo BUT all gunshops will carry it, most sporting goods stores will carry it and even some of the big box stores will as well. The ammo will be more expensive compared to the 308. The 7mm08 will be harder to sell should you want to sell it. This is where the negatives end. The 7mm-08 will shoot flatter with less recoil. I personally think it is the best of the 3 for whitetails and even more so if you reload (because ammo availability does not matter). The 6.5cm is a great cartridge but I still think it is too new to see if it will hang around or if it will go the way of the dodo. If this is your first gun and you are not recoil shy, you certainly cannot go wrong with a 308 (and maybe id pick it just because it will be easy to sell should you want to get rid of it). If you are not new to hunting/shooting and you will hold onto this rifle, then id highly consider the 7mm08.