338
I believe the 338 Lapua was originally optimized for 250 gr +/- bullets. But now companies like Sierra make the 300 gr match kings BT that I now use which have very high ballistic coefficients. Technically the 338 Lapua brass cartridge volume is under its capacity to drive the 300 gr bullet up to 2900 fps (more ideal fps) without going over SAAMI pressure specs. The question could be: Does a 300 Win mag have a better bullet (better coefficient) than the sierra .338 300 gr (coefficient of 0.768) bullet? Will the higher velocity of the Win mag outperform that of the slower 300 gr .338 bullet? The savage 110 that I use has the proper twist rate for the 300 gr sierra, it seems to be accurate- although I'm still testing it. Longest confirmed sniper kill is 2706 yrds with 338 lapua. 2nd longest kill is with 50cal BMG at 2657 yrds.
I shot my Savage .338 a month ago at 1767 yards (1 mile + 7 yards), thanks to my new Bushnell fusion 1600 arc range finder (nice to be able to range that far). At 6X mag, 73.9 MOA correction (turrets + mil hold overs). Note: I'm using the term MOA for IPHY (inch per hundred yrds). Estimated spread 3.5 feet (a bit shabby but preliminary results). Its 0.5″ at 100 yards. Load: 300 gn sierra match king, with 86.5 gn of Retumbo. Muzzle velocity avg. 2648 fps. Nikko Sterling 6-24X 56mm obj scope, which has 63 turret MOAs total but 6 to 10.5 MIL lengths depending on how you use it. Using Knights Armament ballistic program(KAC Bullet Flight Military Version 3.1.0) on my iphone. Temp 99 deg F, 27.5 InHg, angle of shot 3 deg, 15 mph wind at 8 o'clock, Alt 2400 ft, RH 30%.
Shot it again two days ago at 2440 and 3000 yrds, it was 149.3 MOA and 231 MOA corrections, respectfully. For 3000 yrds, I had to use bottom of scope field of view plus 9.6 mil length hold overs and maxed out turret MOAs (at 6X). Had to use mountain to measure the mil lengths. Final fps = 815, time of flight 7.318 seconds. Documented both outings with panasonic camera with 70X optical zoom. Was only able to barely see 3 bullet hits out of 20 shots where I wanted them to land. Too much mirage in 99 deg F, too far with too much zoom to make positive visual hits, and ya it was too difficult doing hold overs. Not enough money for scopes that have 150+ MOA turret adjustments and bigger fields of view. Next time I shoot 3000 yrds it will be at 85 deg F or less to reduce mirage effects. I will post videos on youtube since I now know about the "web video" feature on the camera. I'm also making a 2.5 degree negative cant picatinny rail to tilt the scope down to hopefully eliminate hold over shots. I will see my target in the scope.....
Good shooting gentlemen...