Seems like a lot of stuff for a first rifle. I'd say the 308 will work fine but you might not care for the recoil unless of course you've already tried one. My though on a first rifle would be in either 260 Rem or 6.5 Creedmoor, maybe 7mm-08 but first go I'd say a 6.5. Can't help on factory ammo as I haven't shot any in a lot of years. And then that would probably elminate the 260 Rem, just not that popular. But I'd think there's plenty of ammo around for the 6.5 Creedmoor and 7mm-08, both very popular. As for bullet's, in the 6.5 CM I'd start with 130gr and try 140gr and see which one I shot best. In the 7mm-08 I'd start at 140gr and 150gr. For a rifle, if you like hunting or simply shooting, I'd start with lower cost rifles till you get a feel for what you want to do. You can always up grade. The entry level Savage is supposed to be a good rifle but I've never shot one. sure a lot of people singing the praise for it though. Same thing with the Ruger entry level. I have two Mossberg Patriot's I tried just for grins and really can't complain about it. Great shooting rifle's! There is a thing that bother's me with them but at this point it's not worth mention as it would involve re-bedding and you ain't there yet. They have an adjustable trigger and both came from the factory set at 2 1/2#, they are very nice. Whatever you decide on I would not go with a custom trigger at this point. Learn trigger control and you can fire most any rifle well. Custom adjustable trigger's won't do anything for you you'll recognize for awhile but they will set you back another $100+! I have never felt the need for a custom trigger. On my Rem 700's I have the trigger's set to 3# and most people that have fired them think they are lighter. My Mossberg trigger's will get the same thought's should anyone ever fire them. Something with the light custom triggers, early on with what ever you choose you will probably develope a bit of flinch. All that noise and little shove and it's normal. That is why I say first learn trigger control. Awful easy to jerk off a shot with a light trigger! As for stocks, that pretty much a personnal choice I think. There can be no doubt that the plastic stocks work and in many cases well but I am a wood stock guy. I got a Rem 700 ADL for christmas one year had a plastic stock, worst shooting rifle I ever saw. But I got the stock off and completely re-bedded it and turned it into a real shooter, much better than needed. Today even though I got it going it has a wood stock, my own preference. My 243 Mossberg came with a plastic stock and I shot it very little as I ordered a wood stock when I got it home. With the plastic stock it went well under an inch with test loads, much more than required for a hunting rifle. Keep in mind that most shooter's, especially handloader's scoff at a rifle that only shoots 1" groups but the taget on a deer runs about 8" depending on the target you choose. Therefore a 1" rifle is more than adequate. Also how well the rifle might shoot is going to depend a lot on you! Nothing replaces good shooting habits! I have this feeling about rifles these days, with handloads I strongly suspect any good andloader can make a facroty rifle shoot close to 1" groups right out of the box, even the inexpensive ones! Rifles have come a long way, even inexpensive ones. Which brand is best is another personnal choice. I like Rem 700 ADL's, I get along really well with them. Have had three Sako's years ago but these days I simply can't afford them. have had a couple Winchester's. and my only complaint is I don't have enough experience re-bedding anything but round actions. My present Model 70 Featherweight I paid about $750 brand new for and the only thing I've done with it it adjust the trigger to 5#! it came at about 7#. Thing shoot's right at 1" groups and just a bit over right out of the box. I could not blame a poor shot on that rifle! keep something in mind looking at new rifles, you can always find a rifle that will cost you more but you may never find one that shoot's better than what you have. Aside from how it shoot's, which you won't know till after you fire it, looks are really important the me and feel just holding it and aiming it. Find a rifle that looks good to you and feels good holding it. Don't ask what feels good feels like, you'll learn in time they all seem to have a feel that will appeal to you or not. I think the Browning rifles are beautiful rifles and report's are they shoot very well. But I can't stand the bolt on them and wouldn't get one for no other reason. Now an older browning on a mauser action would be a different story for me but can't afford one.
I think what your gonna find is that few rifles have any huge advantage over another. All will shoot well enough for hunting rifles even if you wish it would shoot better. In time you just may learn how to make them shoot better but that's seem's to me a tall order for a first rifle! You could go the custom route if you can afford it and doing that other than finish you'll never realize just how little you really got for your money if all you want is a hunting rifle. Think about this in shotguns. I have a brand new CZ Bobwhite in 28ga SxS with double trigger's. Cost me about $500 brand new. If I had the money I could have got a brand new Purdey in 28ga, SxS and brand new about $100,000 and I understand a one year waiting period. You know what the Purdy will do for me the CZ won't? Bragging rights, not one other thing!
Spend your money wisely in the beginning, might surprise you how well you can do and if your not happy, you can always spend more on the next one! Before trading out parts from origional factory parts, learn to shoot the factory rifle. Down the road you'll probably figure out what YOU want and won't have to ask! We are all different and have different ideas onwhat makes a good rifle but I'd almost be willing to bet that the vast maajority of hunter's in this country shoot a factory rifle and what worse, if they have been using it long, swear by it!
One more thing about factory parts and it's trigger's. Savage earned a huge ruputation for accurate rifle's with their early model 110's. Thay had the worst trigger i have ever seen on any rifle but people learned to shoot them and they were super accurate! The most sucessful thing you can improve on any rifle, is the shooter!