IF the Do All Rifle is also The ONLY Rifle, then the equation changes...
An AR-10 with a chrome-lined barrel fulfills every role possible. The .308win chambering offers Best Barrel Life and will shoot mild loads to cast bullets and 7.62x51 loads. Magazine length loads depends on bullet design. Not gonna tolerate VLD bullets, except if single-loaded. Premium bullets and 168 or 175gr BTHP offer great versatility and penetration.
The AR design can be Very Accurate. Much easier to gunsmith an AR than any bolt gun. One lower receiver, several complete uppers. 16" carbine and 24" match barrel gives dual duty potentials to one "rifle".
The integral Picatinny rail enables superior accuracy and scope swapping. Usually easy to buy spare parts for repair reserves. Most common parts to replace: ejector, extractor, firing pin, springs for each, trigger springs, maybe a detent ball spare or two should one get lost if ever do a full tear-down. Keep a spare Bolt Carrier Group and barrel extension, maybe a gas tube in each size for each upper.
Chrome-lined barrels aren't a poor choice for accuracy. If ever need to fire more than a few rounds in a hurry, your barrel throat isn't gonna be toasted. The FN-H Patrol and Police bolt guns offer chrome-lined barrels and Win CRF cloned action. Very high quality. The Hogue full alum bedded stocks are pretty nice, especially the non-slip finish.
Similarly, the AR-15 varmint uppers can deliver great range if fast twist barrel is included. A 1:6.5 twist enables use of the 90gr VLD matchkings and other customs. Single-loaded, but they deliver out to 1000yds. A 1:7 or 1:8 twist should be fine for the mag length 75 & 77gr bthp match bullets. These perform at sub-moa if you can shoot them out past 600yds. With next to no recoil and match capability lots of versatility here, plus you got Nosler Partition in .224cal.
Magnums like .224 & 6mm WSSM have been chambered in the AR-15, along with 6.5 Grendel and .50 Beowulf; the 6x45 is another option and the 6.8sc... In AR-10, Armalite chambered the .300saum; & the .450marlin and other saum neck-ups have been done. The .458 socom is another excellent ctg that delivers 400gr cast bullets and the 300gr jacketed & on up bullet weights. One lower and a couple of uppers and you got bases covered. Bound to be a 20 or 17cal necked down .223, for real tiny varmints.
I'd say the Do-All rifle is an extremely practical proposition when compared to trying to make-do with a big magnum. The smaller, older, belted cases can be downloaded with med burn rate powders, but anything with a capacity more than a .300win mag is probably prone to detonation with partial charges. The Lyman Cast Bullet Handbook is worth owning if you're interested in cast bullet loads in your large magnum. However the 10gr Unique "universal" load is N/A when it comes to big capacity cases.
Not many bolt rifles can be bought with spare bolts over the counter. Sako is the only one I can think of, maybe Blaser... The AR 15 & 10 are super choices for durable, accurate, and easy to field service/repair rifles.