Home Forums Reloading Big Game Rifles 338 Win Mag question

I have a Model 70 338 Winchester that doesn’t shoot very well: 3-4 inch groups with Remington 225s. Admittedly, this is the only ammo I have fired through it, but a previous owner bedded it then sold it for a song so I suspect it may have had accuracy issues before.

It seems to have a very generous chamber. The shoulder on fired rounds measures about 2.070; SAAMI specs show 2.040 as shown in the cartridge drawings in the Hornady Manual. The throat is also long: when seated to the lands, most bullets are giving a COAL of between 3.40 to 3.42 so even seated .05 off the lands they are exceeding the max COAL. The magazine box will accommodate a length of about 3.4 so I can just seat the bullets out closer to the lands. I can also neck size and not set the shoulder back, but I am not sure if that is the accuracy problem. Another issue is that I only have a few of the fired Remington cases but have 100 new, unfired Winchester cases, which I would rather use.

So, should I try to work up an accuracy load with the Winchester cases before I fire-form and neck size them or is that pretty much a waste of time? If the latter, what is a good cheap way to fire form the brass for a better fit in my chamber? I have a couple hundred Hornady225s and 250s to use, but if there is a cheaper projectile or way, I’m all ears.

Also, this is my first loading project for a belted magnum. Most of my reloading has been for a very forgiving 30-06. Andy advice, tips or tricks for loading this round would be most helpful.

Finally, any pet loads with RL19, W760, Hodgon or IMR4350, or Varget would be appreciated.

Thanks for the help. (I hope I'm not asking for too much!)

If you have any H4350 that's the powder to use in the 338 win mag! I used 71.0gr with 225 bullets and 69.0 with 250's...

I've never experienced the issues that you are having,but here's my thoughts for what it's worth.Fireform your brass,do minimal resizing(not setting the shoulder back),and try some Barnes 225 TTSX's. Barnes Bullets generally like to be seated well off the lands,and may work well for your particular situation. Good Luck! memtb

I have had good results with two 338's and 225 bullets using 74gr. of R-19. Near max load so work up. With 250's R-22 has worked very well at 74 or 75gr. also near or max loads. For a reduced recoil load with 225's 57gr. of IMR4350 shoots great at about 2400 fps.

Speedgoat,

I have your exact same rifle, and it too has a large chamber and very generous throat.

As 79s mentioned, one very good load is also 71gr H4350 behind a 225gr NAB. However it does not like bullets seated to the lands it like the OAL at 3.330, which is a huge jump, around .25, but most of my Winchesters are that way.

In this particular rifle I've moved to a Forster neck sizing die, and at some point will add a Redding Body die for when I need to bump the shoulder.

antelope sniper is right. Longish throats and generous chambers are common with M70's and belted magnum chamberings. This is to make sure they safely swallow a wide variety of factory ammo and still go bang.

Some bullets and loads will make the "jump" better than others. Some people don't like this arrangement and swap out mag parts for a H&H arrangement so they can seat closer. I've "fixed' some 300 Win Mags this way, but it usually isn't a problem to find something that will shoot.

Seat bullets straight,use loads approaching max,and something should fall together. I wouldn't worry that one factory load did not do well. Not unusual.

RL19 is another good powder to try.The 338 is a good flexible cartridge, easy to work with.

I also had two different .338s ( an old ruger 77 and a 1968 vintage Win. Model 70) And they both liked 74 grs. of Reloder 19 and 225 hornady spire points. The winchester would average under .75" with that combo for 5 shots over the 15 years I owned it. The ruger was around an inch...... never chronied either just killed stuff with Them !!!!!!!

I use the above mentioned load in my Howa 1500 338WM with good results. IMR 4831 might worth a try if H4350 cannot be found.

Thanks for the help everyone. Based on the advice received thus far, I think I will fire form some of my Winchester cases with a reduced load and then start work ups in earnest and aim to get a load if not at, then near max. I've never been too concerned about max velocity but I have heard before that many of the magnums shoot best near a max load; the info you all have provided corroborates that view. Guess I'll get to see for myself what happens in my rifle!

Since I have a bunch of Hornady 225s I'll start there. For those of you with experience with that bullet, how far from the lands would you seat the bullet to start?

Thanks again for all your time and thoughts.

Speedgoat I can't tell you OAL with the 225 Hornady. But I can tell you to back off max charges worked up with the 225 Hornady if you switch to another bullet. It has less bearing surface than some other 225's and will take heavier charges.

I found this out the hard way.

Keep in mind that the 338 isn't really much of a magnum, other than by headstamp, when you consider the expansion ratio. It really is more of a '30-06' in the 33 bore diameter so you should find quite a bit of flexibility in it.

Speedgoat, I suggest finding what your rifle likes.

Start at magazine length, and work up your load. It may shoot just fine. Then work with your OAL, always working in. This will avoid pressure issues since increasing OAL can increase pressure.

This book has a chapter devoted to special issues with belted magnums.

http://www.amazon.com/Precision-Shooting-Reloading-Guide-Brennan/dp/1931220123

From my reading of it and your report, your brass will last much longer and probably perform better if you only neck resize, not full length resize(until the extraction becomes hard), after fire forming to develop your best load and OAL.

Thanks again everyone. Great info, I really appreciate the insight. Those lessons learned the hard way last a long time don't they! I've learned a few of those myself over the years...Enough so that it is sort of fun to watch my two boys learn the hard way. I can tell 'em but some lessons they just have to learn on their own...

I'll work up slowly and start with them seated as close as the magazine will allow. That was a great bit of advice too; I never thought of it but so obvious now that you told me.

It might be a few weeks before I can get to the range, but I'll let you know how it worked out.

Thanks again.