I have all my rifles built, once I put 2000-2500 in a rifle whats a 600 dollar rebarrel every 5 years, after using the large cases since 1986 my thoughts are, figure out your max range you wanna take your game, say its 750 yards, choose a bullet that has a high BC, and is known for performing well. figure the velocity you need to have the required energy at your max range, choose the smallest cartridge that will give the needed velocity, buy the parts have a smith screw it togather. you have yourself a rifle with the most longevity possible to do what you need to do.
I have a 7mm stw basicaly a 25 year old 28 nosler, maybe a bit better performance, but for long range shooting you can put a 30" barrel on a 7mm practical (7mm/300 winny) and get the same performance as a 28 nosler and increase barrel life 2X
I've posted about my 6.5 gibbs a lot
look at the numbers here
from nosler
the 26 nosler runs a 140 at max 3303 fps burning 88 gr of powder
the 264 runs it 2970 burning 59 gr of powder
my 6.5 will run a 140 berger at 3200 from the 29" barrel and only burns 61.7 gr of powder in a modified 270 case
to put that in perspective the 26 nosler burns 42% more powder to gain 3% increase in velocity, there are many gibbs rifles with button rifled barrels that will outrun the 26 with a 30" barrel, mine is a kreiger cut rifled 8 twist so it runs a bit higher pressure than button rifled so my loads are slower.
RR