I have recommended the .223 elsewhere, and would be very comfortable shooting it a lot out to at least 600yd. It's just a bunch of fun with a reasonable price tag.
For beyond that, I fall back on the .260 Rem, which I've been shooting out to 1000yd since the year this site was initiated, competing maybe 2 or 3 years at the full distance during that full span. I know the 6.5CM is the more current rage and it's a great chambering, but I'm invested in the 260, and I honestly believe there is a velocity advantage with it over the CM. My current .260 barrel is 28" long and drives 140's at a good 2850-ish fps. It's mounted on a factory Savage 10FP action with some nice bells and whistles (McMillan A3, Sharpshooter Trigger, and a Mueller 8-32x44 scope ). Not the most envied approach, but very adequate to my own abilities.
I too believe in going directly to the chase, and am not really a devotee of custom builds. I have a strong preference for Savage Factory rifles, and they have stood me in good stead since when I first started buying them in 2000. The modern models with factory varmint weight barrels are probably capable of shooting to the abilities of most of the shooters on this site, when handloaded competently.
I am currently in possession of a Savage 11VT .223, and another identical one chambered in .308. The factory barrels will shoot well under 1MOA handloaded competently. Savage is a rifle brand that lends itself very well to owner performed barrel replacements, which I have done myself on a number of occasions. Your scope will merge nicely with a Savage heavy barreled rifle, and serve as a very adequate trainer once skills evolve to the point where a full-on custom build is seriously warranted. Most importantly, it can get you onto the distances ASAP and with a lesser outlay.
Not the cheapest by a healthy margin, the
Savage 12 Long Range Precision rifle offers a very well featured package with a 26" barrel, chambered in .243, .260, or 6.5CM. for just under $1300. It's a respectable entry into LR precision shooting.
Greg
PS Aw, heck, I just saw your latest post. Well, I think you're going to be happy with your chpice, and wish you and your Dad much pleasure in your new shared pursuit.