I built a budget long range varminter last spring using a Savage 16 (originally chambered in 300 WSM
). I installed an 8 twist ABS barrel chambered in 223 WSSM. The round feeds without issues from the magazine. I tried 80 grain match kings, Berger 80 VLD's, Nosler 80 grain and got great accuracy but poor terminal performance on prairie dogs beyond 400 yards. I switched to 75 grain Moly Amax and had a great time launching prairie dogs out to 900+ yards last July. I get well in excess of 3650 out of the Amax using VV N560, sub 1/4 moa and got redmist out of the targets out to about 700. Between 700 and 1000 the bullets have much less explosive expansion but still kill quite well.
Accuracy was never an issue with the MK 80's. They were consistantly sub 1/4 moa, they just didn't give the explosive terminal performance I require.
Sure, there are issues with the WSSM. You have to be nearly right on top of max chamber pressures to get the case to obturate. With .018"+ neck walls go figure. However, this is a short fat powder column that exceeds the capacity of the 22-243. With a little load development and enough barrel length you can make it sing.
We were limited by terrain in the distances available last year and couldn't get past 970 yards. This year we are hitting a different town with opportunities out to 1500. I'll be shooting this stick again this summer at longer ranges.