Help with first rifle build

I'm looking at building my first rifle. I have a 300WM for hunting elk, but would like something with less recoil, can be used to practice long range, and is more enjoyable to shoot so I can work on my fundamentals. I'll use it at the range and to hunt Pronghorn and Deer (maybe) with it. 6mm/.243 is the smallest caliber we can hunt big game here in CO. I'm thinking of the below setup. Thoughts on the caliber or setup? Anything I need to double check given the below list? Can I use AICS mags with this? Thanks and Happy New Year!!!

PBB Tikka T3X prefix SS Matte 26" 6mm Creedmoor, 3R 7" twist, #3 sporter, flutted. I can wait the 12 weeks or so.
EC muzzle tuner
JA Tikka T3X SA 308 action, flutted bolt w/mag
Trigger - Will try the Tikka out that comes with the action.
Chassis - MPA BA Hybrid(or lite?) or KRG Whiskey 3
Scope -TBD

Just my opinion, but for hunting I would step up to the 6.5. Still basically zero recoil but will carry more energy.

Thanks @The Oregonian
Going with a 6.5 CM would definitely make things easier. Possibly start with a built rifle for the barreled action. Any other advantages of the Tikka fluted bolt other than looks?

If you run the numbers between a 6CM pushing a 115 VLD @ 3085 and a 6.5CM pushing a 140 @ 2750, they are nearly identical at 860 yards for retained energy. I always use 1800fps & 1000ft/lbs as a minimum on deer-sized game. 860 is the yardage both of those drop to either 1800fps or 1000ft/lbs.

That being said, I would still opt for the 6.5 as well for deer hunting. More bullet mass for more shedding of shrapnel inside.

Do you have the Tikka in hand? If not, I would do a Barreled action based on a Bighorn Origin.

The Oregonian said:

Just my opinion, but for hunting I would step up to the 6.5. Still basically zero recoil but will carry more energy.

Click to expand...

2nd This!

That's 3 suggestions to go with 6.5 over 6 CM. Maybe I'll just pick up a Tikka T3X Lite or SuperLite for $800 - $900, thread the muzzle, and replace the stock with a chassis?

6.5 is a good choice. Consider 25-06 8 0r 7.5 twist or 25 Creedmoor.

Out of curiousity, what's your 300 put together like and can you basically dupe it with your next build?

Personally, to me a combo of the 300 and a 6 of some sort covers a lot of territory.

My 300WM is a factory Browning X-Bolt Hell's Canyon LR. Added rings, scope, muzzle brake, and bipod. Nothing else modified. I hate the mag, rounds get stuck. And I'm guessing it's a cheap stock.

Worked up some good handloads. Was hitting 1000yd targets yesterday. Super fun but it's a canon and I can't see my shots.