338-378 WBY 260 grain Cutting Edge

[Long Time Long Ranger]

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.

 

[Long Time Long Ranger]

This picture shows the 338-300 RUM loaded with the 225 grain CE bullet and the 338-378 WBY loaded with the 260 grain CE.




This picture shows left to right the 225 nosler accubond, 225 grain d62 CE, 252 grain max agg CE, 260 grain CE and the 300 grain SMK. You will notice the 225 grain CE is about as long as the 300 grain SMK. The CE bullets are very long per weight bullets. The 252 and 260 grain CE bullets are longer than the 300 SMK. They are really beautiful sleek bullets and shoot as well.

 

[jayran]

Good post thanks for the data. I have been kicking around what 338 cal to go with for my next gun, but not sure what caliber. I have an accumark in 257, so i was lookong on weatherby's site and see they came out with the 338 lapua in the accumark. I like lapua brass but how much difference in velocity is there between the 338-378 and the lapua? Thanks for any input/ advise.

 

[ICANHITHIMMAN]

I love the increase in velocity your getting. I thing the lighter weight bullet may be on its way to my house soon for testing in my 338RUM.

 

[Long Time Long Ranger]

On average the 338-378 is about 150-200 fps faster. Just depends on the rifle. All the big 338's are close enough that if you get a slow barrel 338-378 and a fast barrel 338 lapua there will not be much difference. A fast 338-378 and a slow lapua and there is a lot of difference. In the 26" barrel Accumark you will average maybe 150 fps difference. Either will kill anything.

These light, high bc bullets can give you an advantage depending on how far you typically shoot. Where they really help is the extreme accuracy from a perfect cnc cut bullet over a swaged lead core bullet. They are not very critical to load for to get extreme accuracy. I have never shot a more accurate bullet. For some reason I can get higher velocity by 75-100 fps over the same weight lead core bullet in several rifles and this combined with the weight/bc ratio gives an extra advantage. The only one that is not is my 264 STW which shoots the 129 SST about the same velocity as the 130 CE with best accuracy.

With the 260's they recomend a faster twist than 1-10 however this rifle is shooting them well at 3300 fps.

 

[ICANHITHIMMAN]

Very exciting thanks a lot.

 

[jayran]

Thanks for the reply good info!!!