The .338-378 Weatherby Revisited Part II - Conclusion

There’s just something about squeezing the trigger on 80 lbs of recoil that makes shooting a larger bore Weatherby such a special experience. I’ve found it advisable to keep a good selection of screw drivers, Torx head drivers and loctite handy to keep all of those fine fasteners securely attached to the gun and scope. No, I am not being critical of the Weatherby, but I am suggesting they are not the sort of gun to take to the range every weekend and pound out piles of empty brass. They are absolutely fun to shoot, are very accurate and very reliable for the purpose they were designed, hunting.

I wanted to offer a few observations on the bullets selected for this round of handloading for the .338-378. The load data and exterior ballistics information follows, in case you’d like to skip the comments and go to the conclusions.

Bullet construction

Outside of the Barnes and Swift bullets, there was nothing all that different the way of jacket construction from the remaining manufacturers. Woodleigh indicates they use a special 90/10 gilding metal (10% zinc) and a core of lead fused to the jacket…okay – but virtually all current volume manufacturers use a process to bond the core to the jacket. The jacket of the Woodleigh is spec’d at 1.6mm, however, the one’s I checked were 1.1mm, the same as the Speer and Sierra cheap seat bullets. None had a discernable taper in the jacket material as the jacket progressed toward the bullet tip. The Barnes is of course solid copper, and the Swift has an open base “A” construction allowing lead to be loaded at both ends of the bullet.

My only point is that all of these bullets are well made, but none appear to be particularly special. I’m beginning to believe the Woodleigh price tag is mostly the result of importing bullets from a country that made firearms illegal, than the result of exceptional construction or high levels of quality control. I’m sure if your shooting a large bore (.40+), particularly a double, Woodleigh may be considered a top game in town, but for high velocity bolt action applications, I can’t see the big deal. 

Heavy bullets for the .338 bore

Bullets with high ballistic coefficients and high sectional density do a good job of holding onto velocity, energy and stability. The .338 bullet selection is very good, and at 250 grains typical sectional density is .313, better than a 7mm 175 grain slug and much better than the .308 bore heavy bullets. While I did try the Swift at 275 grains, after reviewing external ballistics, there was probably little reason to cross the 250 grain line. I didn’t test an ideal bullet for the .338-378, but there is a good chance it doesn’t exist at this point in time. The closest I could come to optimal, with an off the shelf bullet, would be the Sierra 300 grain HPBT match with a BC of .768 and an SD of .375. If I could launch a 300 grain bullet designed for hunting at 3,000 fps, and I believe the .338-378 has the potential with H1000 Hodgdon, I’d still have over 4,000 ft/lbs of energy at 450 yards, and I’d be under +/- 5″ trajectory out to 380 yards. The fact that my shooting skills fall away at 200 yards is a whole different issue.

What I believe is keeping an almost round nose on most of the heavy .338 bore bullets is the .338 Winchester legacy. With 83 grains of case water capacity, the .338 Winchester is a 2,600 – 2,700 fps cartridge with a 250 grain bullet and a 2,300 – 2,400 fps performer at 275 grains. Because the .338 Winchester represents the large installed base of rifles of this type, there has been little commercial reason for bullet manufacturers to produce very high BC/SD bullets for very high velocity .338 bore rifles. For the past few years, however, cartridges for  the .308 and .338 bore based on  the 404 Jeffery and 416 Rigby cases have become very popular in volume factory rifles.

At 275 grains, zero’d at 250 yards, the .338 Winchester can marginally reach to 300 yards and arrives with approximately 2,000 ft/lbs of energy. With the high capacity .338 cartridges, you could go up to a high BC 300 grain bullet pushed to 3,000 fps, reach out to 400 yards +/- 5″ trajectory, and still be carrying over 4,000 ft./lbs of energy. At the 300 yard mark limit for the .338 Winchester, the big cases would retain over 4,500 ft/lbs of energy. But I’m making it sound as though the big cartridges are only for long range shooting, and that isn’t my intention. At the muzzle, KE for the .338 Winchester 275 grain load and the .338-378 Weatherby are respectively 3518 and 5497 ft/lbs. However, what is probably needed is heavier bullet construction to handle the added velocity, like the construction employed by Swift and Barnes, but with more streamlined package.

Coatings and bore wear

I think coatings with a reduced coefficient of friction, like generic moly or Barnes and Combined Technology proprietary dry film lubricants, do reduce bore wear and reduce velocity loss to friction in equal bullet comparisons. I couldn’t see the gain with the Barnes bullet compared to the Speer bullet of the same weight, but I probably would have seen it if I compared the Barnes XLC to a Barnes X. I don’t think bore wear reduction, as a product of bullet coatings, is all that meaningful. It seems more barrels croak from throat erosion caused by high pressure and temperature directed at the chamber/bore transition, than from wear caused by actual contact between the bore and the bullets bearing surface, at least in the case of grossly over bore capacity cartridges. Can’t help but think there is some ceramic coating process, or plating process out there…..

.338-378 Handload Data

These are loads that worked for me and check out in my gun, under local weather conditions, using handloading supplies from by loading bench. I don’t know how well they’d work for anyone else, so if you intend to try any of them, knock of a few grains and work up. I left off the decimal place group sizes under 1 MOA. I was receiving too many letters from people who tried loads and we’re ticked because they couldn’t get within a .25″ or .50″ of the indicated group size of a specific load. Actually one guy couldn’t get within 5″ or so in group size with any of the listed handloads. Worse still, people were routinely writing to tell me they were shooting much smaller groups than I indicated. The point is, if the load is under an MOA, it has a propensity toward accuracy and worth exploring further.

In general, full cases are more accurate and consistent than lower volume charges. H870 may be the exception to this rule, including those H870 loads requiring modest levels of compression. Unfortunate because it’s one of  the few powder types that are relatively easy to meter. I think if I were to select two power types for the .338-378 it would be RL25 and IMR 7828; RL25 for the heavy bullets and IMR 7828 for the lighter bullets. The best all around may be H1000, but that will be part of a future assessment.

Brass is holding up with the exception of two pieces; one I accordioned in an out of spec early die set, the other I welded to the bolt face when I got a little too aggressive with powder and  the temperature rose 30 degrees Fahrenheit during the course of the shooting day. Primer pockets are intact, no pressure rings inside the cases and no signs of fatigue at the neck and mouth. I do, however, have about 30 tons of excess .338 bullets on my bench.

.338-378 Handload Results

I hope the information proves useful and I will update the handload data section for the .338-378. 

 More “The .338-378 Weatherby Revisited”:
The .338-378 Weatherby Revisited Part I
The .338-378 Weatherby Revisited Part II
Handload Data 338-378 Weatherby Magnum

Thanks,
Joe