300 WSM Build

Looks like I am going to be building off a long or medium action lol. Thanks for the info! Really new to all of this and the rabbit holes are deep
I just had my 300 WSM built off a BAT Vampire action (medium), Mariner MCS-EH4 stock, Oberndorf bottom metal M4 and 22” Bartlein 1-10. Shoot crazy accurate with 180 Hammer Hunter
I built on a Defiance XM action. The throats cut for for Berger 215 hybrids seated to the shank/boat tail junction and just touching the lands. Don’t know what the COAL at the moment but cartridges fit the magazine with room to move bullets out as the throat erodes.
I bought my components from Ryan Pierce he had a great deal on the Kelbly LA and a Proof 1-10 twist 22” barrel. I sent it to Alex Wheeler to have it threaded and chambered. He’s got a badass reamer for the 185 Juggernauts! If I was you I’d suggest grabbing that action from Ryan and going the same route.
Going to buy a Kelby Atlas Lite action- If I purchase a short action, do I have enough COL with a Watts extended mag box? or should I just build it on a long action. Trying to build a light pack hunting rifle. Thanks in advance for any help!
reamers don’t cost that much. i’d just buy a reamer throated for the bullet you want to use.
Not going to try to talk you out of a Atlas as they are excellent—but I’d go like the other above poster and go Tikka—it’s light—comes with a great trigger and starts with a good trigger about $400 less…but cannot go wrong with a XM or Long action
FWIW I have a GA precision SA with aics style drop mag, and view the whole setup as mediocre - it's close to 15yrs old now tho. Geez. That said I get 3050ish with 175g Berger and (used to anyway) ragged holes that are now starting to open up to 1". It's not light with a #5 Bartlein either. I remember my disappointment after reading Litz's first book a few years later, not being able to load past 2.1 except 1 at a time. A dremel helped..but what I don't get is why give up powder capacity if you're gonna go with a LA anyway to launch heavies? I've had some good hunts with that rifle, not knocking the round, but if I was gonna do over I would also go LA, and if I was gonna do that, why not launch it faster than wsm can? Asking out of ignorance, but it always seemed like I moved backwards in performance from the custom 300wm I already had.
I built mine off a tikka action. hca heavy hunter AG composites stock. LOVE it built by Dallas Lane