What! My son was shooting my .416 Rigbys when he was 15 and only weighed 165 pounds. It's not that bad. I have two, a No. 1 and a M77 and the No. 1 with my elk load is 325 gr at 2960 fps, well, that one gets your attention but it is not going to knock anyone down, but the M77 with its load of 400 gr. and 2400 fps is a pussycat to shoot.
Save your money in regards to fluting. If anything, if not done correctly, it can ruin a barrel by inducing stress. I have barrels of same profile and the fluted one does not heat up slower or cool down any quicker that I can tell. The only thing fluting does is save weight for a same profile barrel. And steel barrels are nor corrugated cardboard. If you take two barrels of the same profile and flute one of them, it does NOT increase stiffness. Most of what is said about fluted barrels is BS and is done mostly for cosmetic purposes because we all know, if it looks cool it shoots better and we are suckers for looks.
I do hope you will get the best barrel you can afford. Doing a project like this and cheaping out on a barrel is crazy. That is the most important part of the rifle and if you cannot afford to do it right, then wait until you can. Get a Pac-Nor Super Match, Lilja, Kreiger, or other top tier barrel but stay away from the A&B and ERSHAW barrels. They are OK for standard hunting accuracy but when doing a custom gun for a long range shooter, either do it right or don't do it at all. Cheap out on the barrel and your two-thousand dollar custom build will be lucky to hit a fifty-cent piece at 300 yards. Get a good barrel and you can shoot Kennedy's eye out. I've built several long range rifles for personal use and promise you, cheap out on the barrel and you will regret it. JMHO
Nice pistol. I wish Savage would bring back out those Striker pistols. Mine is a .308 stainless that I had a barrel done in .458 SOCOM. Not a long range shooter by any means but a nice pistol to match my ARs in that caliber. It weighs no more than the standard Striker and recoil is minimal. I have a couple of other projects in mind but unless I find another Striker stainless they will have to wait indefinitely.