Home Forums Hunting & Shooting Hunting Rifles Convert a 300 Wby to a 338 Win Mag ?

Is it possible to convert my Win M70 300 Wby to a 338 Win Mag ?

If it is then what is required to do the conversion ?


Also, Do you think that it would be a good idea to do this ?

Thanks, Conrad

ConradCA,all you need is a new barrel,and a gunsmith to rechamber to .338 WM ,pretty simple! ackleyfan

Since your rifle can handle the 3.60" cases, why not a .340 Roy?

My thoughts exactly, I'd be for going to the 340, it is one of my all time favorite rounds. I'd have a 4.5 weight Schneider put on it and cut it at 25". One last thing I'd do it sans freebore. I've had 4 tubes this way and they have shot incredibly well!

Dogz

and be sure to wear earplugs

Its actually very easy. Sell the Weatherby and buy a Win Mag.

"Its actually very easy. Sell the Weatherby and buy a Win Mag. "

hmm, that might not be a bad idea. That M70 in 300 wby is probably worth some coin to someone. They haven't offered a M70 in 300 wby for quite a while now other than from the custom shop, they dropped the caliber along with a bunch of others when they started pushing short mags. Sell the M70 in 300 wby (or at least put it out for sale, see what sort of bids it gets) then check into the new M70 Sporter III in .338 win mag.
Or, go custom, build your hot rod. But if you're going to screw the bl off undoing what the factory did, then I'd say go big or stay home. By that I mean get your high end custom bl, toss some pillars in, make it real cool.

A couple of points you may wish to consider.

If you convert to 338 Win you will no longer have a true CRF rifle because the shorter 338s will be hard up against the front of the magazine and so the bolt will be able to "expose" a 338 in the magazine before it has ejected the cartridge.

If you convert to 340 Wby I think you will find the M70 magazine to short with some 338 bullets seated to the cannelure. That is the reason that the 338 Ultra was made slightly shorter than the 300 Ultra.

Mike

Sorry Mike, your reasoning is totally lost on me. I shoot a model 70 7mm rem mag that uses a box that will accomodate the 416 rem that feeds, yes controlled feeds, like gorilla snot.

Chuck

Chuck,

I am not referring to the feeding from the magazine but with the 338 hard up against the front of the 300 Wby length magazine, when the bolt is pulled back (with case or cartridge in the extractor) I think you will find the bolt will uncover the 338 case head before the the other round has been ejected.

Push the bolt forward at that point and you would have a double feed.

Mike

I don't see why there would be a problem. You have to pull the bolt back so it is completely behind the cartridge in the magazine before you can push it forwards and load it into the chamber.

Conrad

Conrad

But true CRF is where you can't have the bolt trying to push a cartridge forward from the magazine while there is still a cartridge in the bolt.

It is unlikely crop up in actual use but with such a conversion I could make the rifle double feed every time.

Mike

I've always adhered to the theory that "if it ain't broke, don't fix it".

It doesn't appear to me that your M-70 in .300 Weatherby NEEDS fixin'. You've already got one of the very best rifles in one of the very best cartridges... so what's to gain by the switch?

Frankly, the .300 Weatherby with heavier bullets is easily capable of taking any big game in the new world. And with lighter bullets, it shoots about as flat as any bullet can shoot.

I don't see why you'd even WANT to rechamber a .300 Weatherby when Nosler makes a.308 caliber, 200 grain Partition with a .481 ballistic coefficient & a .301 sectional density as well as a 220 grain semi-spitzer Partition with a .331 sectional density if you want to drive a big, heavy bullet real deep in a very large bear.

I hunted for almost 40 years with a pre-'64 Model 70 Winchester "Alaskan" in .338 Win. Mag.... and while that caliber is a good one, so is a .300 Weatherby. I can't see how you'll gain much of anything by switching.

And, let's face it, the .300 Wby. has enough powder capacity to drive the heavier bullets (180 grains and up) at high velocities yielding tremendous bullet energy.

If you wanna spend some money or get some new "gun-stuff"... and you are not into reloading, you might think about getting into handloading. There's a lot of enjoyment in working up superior loads for your rifle and taking game with your own handloads.

If you're already into reloading, then think about up-grading your reloading equipment or getting a better scope for your rifle(s)... or how 'bout a new laser range finder?

Just my 2�... <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />


Strength & Honor...

Ron T.

I agree with Ron T. The .338 is not much of an improvement, if any, over the 300 Weatherby. You'd never notice it except just maybe on big bears with 250 or 275 grain bullets. You'd get unnecessary recoil and less-flat trajectory for anything else. If bears are what you have in mind, why not rebarrel to 375 H&H. That would eliminate the CRF problem one of the posters brought up.

Mike, you're grasping at perverbial straws here. When you fail to eject a case, in any case, you're on the way up the smelly creek anyway. I also believe you won't find those 338's hugging the front of the box. If you do some follower work needs to be done.

Ask Miller and Echols how they're able to pull it off.

Chuck

Chuck,

But recoil will have the cartridges parked at the front of the magazine.

I did say it is not likely to be a problem in a practical every day use of the rifle. I just made two points, one being that 340s with some bullets seated to the cannelure will be too long for the M70 magazine and the CRF feature will be downgraded, which it will.

I don't think Echols and Miller are going to have much to do with the conversion in question <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Mike

Not in a rifle with a properly tuned box and follower. I shoot a rifle so designed and the CRF feature is not downgraded in any way shape or form, and the cartridges hold tight to the back of the box. As I was saying, guys like Miller, Simillien, and Echols are example's of smiths that do this routinely.

Chuck

Chuck

As I said above, I don't think Conrad
had Echols and Miller in mind with his rebarreling project.

Mike