Re: new to me savage 12fv 223rem
Congrats on the new rifle. Sounds like you got a great deal.
I've had a Savage 12 BGTV in .223, 26in heavy varmit contour fluted 9 inch twist barrel, for a couple of years now, have shot lots of different ammo and agree with most of the above advice.
If you look at the stability #'s for the 75 & 77 grain bullets (for a 9in twist barrel), you'll see that that at warmer temps (75F+) you should be fine, but at lower temps (<55F) the stability gets more marginal. In practice in our warm (read hot) GA summers I've found that hand loaded Hornady 75gn HPBT works pretty well, averaging 0.75-1.0MOA. (Haven't tried the Amax.) In contrast, both the Hornady Steel 75gr & Hornady Match 75gr (commercial loads) just don't seem to shoot quite as well, both give ~1.0-1.25MOA; not bad but not as good as the hand loads. I tend to keep lots of the Hornady Steel 75gr on hand since it's very cheap - my friends can shoot this without using up my hand loaded ammo.
In my rifle I see the best accuracy with the Sierra 69gr hand loads, consistently 0.5-0.75MOA, YMMV. Stability is not a problem with this bullet weight in a 9in twist barrel.
Bottom line: try different bullets/loads in your rifle to see what works best. If you're interested in the best possible accuracy, I highly recommend developing hand loads using the Optimal Charge Weight (OCW) approach or something similar (always start low & work up, watching for pressure signs).
Get out & shoot & have fun!