Gents;

I have a .338-06 built 20 years ago on a commercial Mauser action. The rifle was more or less set aside some years ago in favor of other projects and due to the fact that the chamber seems to have been "wallowed out" when the barrel was fitted. Recently my interest has been renewed and I'm wondering what forum members would consider to be typical "good" accuracy with this cartridge? My best results from different bullets tried were about 1.5 moa from my 1-10 twist barrel. Does this round tend to favor one end of the bullet weight range over the other in terms of accuracy?

Don

Accuracy is not at all related to a round except that there is some correlation of accuracy to caliber as the smaller calibers with less recoil are easier for people to shoot well.

1.5" groups from a 338-06 are not at all bad if they truly represent the rifles real ability.....meaning that you can shoot a 10 shot 1.5" group.

Personally I believe there is no reason that at least a 1/4" can be shaved from that group size with a bit of reloading experimentation.

My own personal .338-06 will do .75 moa at 200 yds with handloads consisting of AA2230C and a Hornady 225.

If you suspect an oversize chamber the first thing I would do is a chamber cast to see just how big it really is. You don't want one too big or you risk blown cases.

If the chamber is only slightly oversized (on the max end of tolerances) then I suspect that you may see some real gains in accuaracy if you neck size allowing the brass to "fireform" to your chamber.

There is no most accurate bullet or load for any rifle. My .338-06 is a good example. It shoots 210gr NPs just under 1" & any 250gr bullet the same on good days. It won't shoot any 225gr bullet/powder combo, I have tried to date, much under 1.75". The barrrel, chamber, bedding, your own shooting skill, all play into the accuracy. Your rifle is giving you a good starting point if you can get nice round groups of 1.5" consistently.
Pick a bullet you want to use & try no more than 3 powders. Play w/ seating depth then try switching primers. I'll bet you can get her into the 1" zone. I love the 210grNP in the .338-06. It seems made for this cartridge. Good SD, decent BC, penetrates like crazy & expands well within the vel. envelope the 338-06 provides. It also is the most accurate bullet in my rifle, but others come very close. Good powders to try are RL15 & IMR4064 for 185-210. I like H4350 & RL19 under 225-250gr bullets. Good luck w/ your new found friend. I think it's one of the better rounds for hunting all of NA.

Fred has a lot of experience and his advise is good. I like the 210-225 Partition with either H4350 or Ramshot Big Game in my 338-06. I only shoot 3 shot groups but can make them all touch at 100 yds.For lighter bullets RL 15,Varget or IMR 4064 are my choices. I haven't worked on the 250's

I have gotten groups around .5" with the 180gr Nosler Accubond & RL15 powder out my 338-06. It is a Remington 700 with a Hart 1:10 barrel. I have also gotten groups larger than 1.5" with it. I think Fred has given some of the best advice. Pick a bullet & some powder & try them to see what your rifle likes.

Mine also 700 hart barrel 10 twist 23" std chamber

IMR 4320 and 200-225's shot 1.25 at 200, and .5 at 100yds. That was best for accuracy/velocity and I researched alot of data and that was what seemed best at the time, I was happy and saw no reason to change. I am sure other powders can duplicate results but there are some powders that are in the 'sweet spot' for burn rate for this cartridge (like many) I believe, and they shine.

I had Ron Smith build a barrel for mine, a 24" Cr Moly with a gain twist ending up about 1:10"
I intended to use heavy bullets in it. It would not group up to 225gr much less than 1 1/4".

250gr Sierra GK and the 250gr Hornady RN were a stellar combo for this gun. My best group was about 7/16" with the Hornady's.
It really impressed my first Bull moose and Black Bear.
Had the best luck for velocity and accuracy from H414 and CCI250 primers.
Had also tried IMR4064,4320,4350 and RL19 with mediocre results.
Mileage in yours may be way different but there's what I can offer.

Noel

Seems like a non issue to me. If you don't want that 1.5 inch gun, just send it to me. I will be more than happy to go shoot big game with it for the next 15 or so years just to see how inaccurate it really is.

I have had real good luck with mine...it will do groups as small as 3/4 an inch or so at 100 yds.. if seafire here can do his part...

Like my 2 338 Mags also, the barrel seems to really like 225 grain Hornady SPs...and Nosler 225 grain Partitions..

tightest groups have been with 200 grain ballistic tips...

Welcome to the AR 338-06 fraternity. You won't believe how many guys on this forum use this caliber.

20 years ago this caliber was still a legitimate wildcat. Yours might not be the same as today's SAAMI's A-Square specs. Just be aware that there are 17, 28 and 40 degree shoulders on this caliber.

Mine is, like some mentioned above, a 24" Hart, 1 in 10" twist barrel chambered in the Ackley Improved 40 degree version. I had it throated for using the 250 grain Nosler Partition bullet. But it shoots the 180 grain Ballistic Tip remarkably well. And every brand and weight in between. Especially the 225 grain Barnes X which I molycoat myself.

It's not the caliber that yields accuracy so much as the barrel and the way it is bedded into the stock. 1 MOA is good accuracy in any hunting rifle regardless of caliber. 1 and 1\2 MOA will bag all the game you want. You might have to tweak your handloads to get smaller groups. It certainly can be done.

I built my present .338-06 in 1977 and it's been my "go to" rifle for big bears moose ect..

When i built it, i knew it wasn't going to be a deer rifle, after all almost anything 25 cal. on up makes a good deer rifle. So i went for "big game" bullets right off.

I don't give a hoot if 200 grain bullets (includeing 210NP's) would be more accurate or not, because they lack of penetration that i want. Although i have shot a LOT of them though...

After much testing i settled on 275 Speers for bears, and they shoot about 1-1/4" groups at 100... That's much better than is needed for big game, so i'm happy with them.

I also have used 250NP's in it as that's been my second choise for big game... and accuracy is similar to the 275's..

DM

Gentlemen;

Thanks for the comments/info. You have helped me to re-focus my thinking about the rifle after a few years of inactivity with it. I DO need to make a chamber cast both to ascertain the chamber and throat dimensions. It IS a wildcat chamber. The barrel was made and chambered by McGowen in th emid 80s. It is a 1-10 twist. At this point in time I don't recall the reason for my choice of barrelmakers but that is immaterial now.
I was never able to come close to powder charges claimed by other shooters of this round so was pretty much on my own as far as loading was concerned. That is true of any rifle to a degree but not so much as this one.
As to accuracy I am recalling thinking maybe the brrel wanted some forend bedding as the barrel is relatively light for caliber. A light barreled 7x57 responded with tighter and more consistent groups after a bit of pressure was added at the forend tip. It is not a BR rifle; I just always thought it should be capable of a bit better and more consistent grouping.
If a chamber cast verifies my suspicions about the chamber, I will have the barrel set back and the chamber re-cut with a SAMMI spec reamer.