338-378 WBY 260 grain Cutting Edge
I just started testing the new 260 grain Cutting Edge bullet .76 bc in my 338-378 wby. The bullet is extremely long, much longer than the 300 grain lead core bullets. The barrel is a 28" Hart 1-10 twist however they reccomend a faster twist for this long bullet. The best load I tried was 122 grains H-870 with an oal of 4.3". The bullet made contact at 4.325". The velocity with this load was 3315, 3314, 3324 and 3321 fps with the 1000 yard string. This seemed to be a mild load in this rifle. Again the velocities of the CE bullet are well beyond where I typically shoot lead core bullets. I get pressure at 3260 fps with the 250 grain Nosler Accubond for instance. After a test at short range I took it out to 1000 yards and shot a 7.2" group which is about where this rifle typically shoots with best loads in the 7-9" range. This was excellent considering minimal load development. I have tons of data with this rifle and various loads so I knew where it probably would shoot the best. The seating depth is what I varied and this accuracy load happened to come in right at the .025" clearance of the seal tight band as CE recommended. So not a lot of load work with this one. Judging as well as this bullet shot in a 1-10" barrel I think guys that can push this bullet fast enough can shoot it in a 1-10 twist barrel.
This bullet with the .76 bc gives this rifle an advantage at extreme range over the 225 grain D62 .64 bc bullet I have been shooting in it at 3510 fps.
I think this is a bullet that is worth trying to get better ballistics than the 300 grain bullets. The habit of the CE bullets shooting faster velocities than lead core bullets plus the light weight and high bc can give it a ballistic advantage over the 300 grain bullets. It is certainly worth a try for guys looking for the best for a hunting rifle. The cost prevents this bullet from being used much as a target bullet. But for the best in a hunting situation for flatter trajectory and less wind drift that also keeps you in the kill zone for a few more yards as your bullet drops through it at long range it is a small investment considering the cost of a hunt.
This rifle shoots the 300 grain smk 3060 fps with best accuracy for comparison. 260 fps with that high of a bc can make quite a bit of difference at long range compared to the 300 grain bullet.
Predictions are difficult, especially when they involve the future