Loading Accumark 338-378

[DRUNK COWBOY]

I am going to find a new load (bear) with a heavier bullet than my current elk and deer load. I will be going to either the 225gr Interbond or the 225gr Accubond (depends on performance).

Is there anyone with a Accumark 338-378 who has loaded with either of these bullets? If so, please provide the overall cartridge length, trim length, primer #, type and amount of powder, type of case and what groups the cartridge is achieving at 300 yards.

I am looking for experience with the accumark 28" barrel with 1-10" twist.

Please no "out of book loads", I want personal experience that came from trial and error

[Grantspastor]

Sorry..I only load for the .338 Win Magnum. Your rifle ought to be a bear stopper for sure. I have found that heavier bullets give the best performance in my .338. I use the 250 grain Speer Grand Slam. Other bullets are good too, but the Grand Slam saved my bacon one day in Alaska when a big bull Moose came after me.

[DRUNK COWBOY]

I would like to go to 250gr, but I am worried there will be to much drop for me to make a good shot at anything over 350 yards. I will be hunting Hells canyon this year and I want a load with enough energy to stop a bear at 400-500 yards. I will most likely be able to stalk closer, but you never know

[Grantspastor]

My manuals show that with a 250 grain bullet you should get a whopping 3000 ft. pounds of energy at 400 yards with about the same trajectory as a 7mm Mag. I don't envy your experience at the range when you work up the best load for your rifle. For the black bears you will be hunting, a smaller bullet would be fine. For big bears I would be a fan of the larger bullets. I have been fascinated with the
.338-378 since I heard about it. Just can't justify (to my wife) the need for such a monster. I will say that I have truly loved my .338 Win Mag for Alaska hunting. It has performed flawlessly on many big game animals. The idea of pushing that same bullet much faster is interesting to say the least. The Remington .338 Ultra Mag looks like a boomer too. Black bears aren't particularly hard to kill, even with smaller calibers. I've heard first hand accounts concerning the large coastal Brown Bears of Alaska that curl what little hair I have left. I think Jack O'Connor was right in his praise for the .270 for smaller game such as deer and even Elk, but I also tend to subscribe to the Elmer Keith idea of bigger bullets=bigger wound channel. Bottom line? the .338-378 is more gun than you need for black bears in Hells Canyon. I grew up in Joseph and have hunted that country. You may indeed have the opportunity to make a long range shot. Congratulations on having the courage to use such a weapon. I would too. My theory has always been "bigger and faster is better" (even if it really isn't)

[Flatfish]

250 grain bullets will fly past the lighter 225s at around 300 yards. They drift less in the wind, and hit harder at all ranges.

Long range shooting is a wind drift game. Trajectory can be figured closely with a rangefinder and a bit of practice. heavy bullets drift less in the wind than shorter lighter projectiles.

Any long range target shooter will confirm what I am saying. 250 grain 30 cal and 300 grain 338s rule the roost in 1000 yard and beyond matches.

Look for a powder that fills the case while making maximum velocity/pressure at the same point. It has been a long time since I talked to many long range bench shooters, but I wanna say that 7828, H-1000, RL-22 Rl-25 range of powders should be a good place to start. I think the big Weatherby case holds 115-120 grains of powder. Look in manauals where max pressure is achieved with this amount of powder.

Federal mag match primers were the poo de la poo when I tried to shoot tiny groups.

Overall length is decided by chamber throat and magazine.

Trim length should be .01" under max spec.

The jump the bullet makes to engage the lands will have huge effects on accuracy. In a quality rifle, I would first work up til I hit the speed the manuals said the cartridge was capable of, and them begin to play with bullet seating depth.

Please consult a manual before loading. A simple mistake in powder will make big problems. Do not ever trust someone elses data unless it is confirmed by a manual.

Hope this helps

Mark and the dog.

[traks44]

what type of scope you have on this rifle?

Heres the problem, your bullet selection for "long range performance" in a 250 gr. bullet is minimal. The most superior bullets will be the Lapua scenar 250 and the Matchking 250. I have read many first hand accounts with people having no problems using thses bullet on long range game(many people actually prefer them). Shot placement is obviously very important. I will tell you why they work so well. These bullets will retain energy better than any bullet on the market, the will shoot more accurate, retain velocity better. The reason there is controversy is that because when they hit an animal they will tumble. Unlike a true hunting bullet which has weight forward to balance it and track straighter into the animal. Would I hesitate to use a 250 grain matching or lapua bullet on a bear. Nope!!!!

I would also consider the .225 accubond. This bullet would also work well. I have shot two bears in my life and both with a .280 at about 200 yards. They didnt go far. I promise you elk are much tougher than bears in this country, but with a proper shot nothing is gonna go far. I understand your possibility of shooting a bear at long range to 500 yards.

If it were me:

I wanted to shoot a bear and would not shoot over 500 yards I would go 225 accubond.

I wanted an accurate powerful round out to 1000 yards with accuracy I would pick matchking type bullet.

My 7mm would kill a bear at 500 yards and yes I would shoot with confidence. Your gun is more than capable and at 500 yards is just getting started. Dont make it harder than it really is. you gotta remember bears will average about 250lbs and the bigger side of 45o. In other words you arent arent really asking anything special of your gun, choose an accurate 225-250gr. bullet and just becaome accurate. Easy as that!

I didnt look at barnes they may have some good bullets?

[DRUNK COWBOY]

Flatfish,

You make some great points. Even for us experienced reloaders. I was wondering if anyone already had a load worked up. This way I take their load into account, but not match their load. I don't wantto blow up my gun.

I am currently running reloader25 using 116.3g of powder. It worked great with a 200 gr bullet out of my rifle. I did not like the weight retention I got with my bullet this year in an elk I killed. So it is back to the drawing board. I have access to a 1000 yard range and we have been impressed with the guns capabilities.

Your thoughts about heavier bullets = better long range accuracy is shared by me as well, But my weekness is judging the proper drop of the bullet to how far the animal is. Thus, I wanted a bullet with a little less drop. It is easy at the range, but when you add an animal into the mix my train of thought goes to Poo Poo.


Trask44,

We have three of the 338-378. The rifle I will be reloading for will have a 4.5x14x52mm with a 30mm main tube. It sits driectly on the barrel. My next scope for this rifle will be a 6.5x20x50mm...I want the extra magnification.