Can I chamber a model 70 .338 to a .340 weatherby or is the magazine well to short?
I dont want another Weatherby.
They are good but I saw a .340 Weatherby built by Marice Ottmar that was nice and was wonering if he used an older .300 or 375 H@H leanght action to do this.I do know it was built on pre 64 model 70 though.

Any 06 length M-70 can be altered to handle the .340 . You may need to machine back the rear bridge to get reliable ejection .

You will also need to change out the mag box to the 375H&H length & after you do there will be a little nib of metal protruding over the top rear of the mag box that will have to be machined away as it will interfer with the top round rising from the magazineto so the bolt can catch it. Also don't forget to shorten the ejector a wee bit.

quote:

Originally posted by cal30 1906:
Can I chamber a model 70 .338 to a .340 weatherby or is the magazine well to short?
I dont want another Weatherby.
They are good but I saw a .340 Weatherby built by Marice Ottmar that was nice and was wonering if he used an older .300 or 375 H@H leanght action to do this.I do know it was built on pre 64 model 70 though.

An H&H Magnum-length action would sure make the job a lot easier!

Find a M-70 in 7MM STW and look at the differences. This is the modifications needed.

Answer is yes it can be done. If I wanted this real bad I'd trade the .338 for a 7MM STW or .375 H&H and start there. But of course you'll need a new barrel then and if you modify the .338 you can retain the original barrel. No matter how you cut the cookie you'll spand about $500 and gain a very small amount of energy/velocity.

When I rebarreled a 338 to a 340 a few years ago, I didn't open the receiver. Just swapped magazine boxes, ejectors and bolt stops. It ejected fine.

That said, when I built a 7mm Rem Mag into a 8mm Mag, just last week, I opened the receiver and redrilled the scope mount hole. It ejects better.

Either way, you have to remove a bit of metal at the rear top of the magazine, cut a small "ramp" for loading at the rear of the mag and open the rails a bit, again at the rear of the mag. The factory gets lazy and doesn't do all this on the "regular" magnums.

Unless you can do the work yourself, and have an "express" length action for a pattern, it's probably better to do like Vapodog says and get a 7STW and just have it rebarreled.

Joe

Keep it coming guys I want to keep the ideas open.

For the cheapest possible conversion , just take a M-70 in .338 and have a smith re-chamber . The .338 magazine can be made to hold the .340 s by drilling out the spot welds that hold the block in the rear of the magazine. Knock that out and you have a magazine about 3.6 inches long . The .338 follower will probably work . Then grind back (shorten) the bolt stop and ejector to the correct .340 length . You may find that ejection is OK , or you may find you need to open up the right side of the rear bridge some .

If I were building a .340 Weatherby on a current Model 70 action in .338 Win. that I already owned and just HAD to use, I would -- as has been stated -- swap out the magazine box, follower, follower spring, and bolt stop with .375 H&H-size Model 70 parts. These are readily-available from Brownell's:

www.brownells.com

I would also have the loading port remachined and opened up for more reliable ejection and easier loading. This is not an option, it's a must for surest operation.

And therein lies the rub: When you start opening loading ports, etc., costs begin to escalate, and one expensive modification tends to lead to another. It might be a whole lot easier and less expensive to look for an original Model 70 Classic in .300 Weatherby, .300 H&H (they made a few), 7mm STW, or .375 H&H at a gunshow, then rebarrel and chamber same to .340 Weatherby. The action parts are exactly correct in every case for .340, and loading port is already properly dimensioned and opened, and you'll also gain the very real benefit of a better barrel than a stock Model 70 tube that you simply rechambered. This is the route I'd personally follow myself.

Keep this in mind: ALL Model 70 receivers (except the 'short' versions) are EXACTLY the same length. In other words, a receiver that came off a .30-06 is exactly the same length as a receiver that came off a .375 H&H. There is no LONG Model 70 action. The difference lies in the size of magazine boxes, followers, bolt stops etc. -- internal parts. The other difference is that Model 70 receivers intended for long cartridges (7mm STW, H&H, etc.) have their loading ports machined differently (opened) by the factory.

All of these options, done right, cost real money. No free and easy lunch..........

AD

Allen: did they make a 300 H&H in a Classic? FIND ME ONE!! jorge

quote:

Originally posted by cal30 1906:
Can I chamber a model 70 .338 to a .340 weatherby

yes, but . . . (1) you'll find very little velocity advantage, (2) the Weatherby radiused shoulder and freebore don't necessarily lend themselves to the best accuracy (in my prejudiced opinion), and (3) if you want extra speed, the .338-8mmRemMag is a better choice (again, in my prejudiced opinion.)

What can a 340 Weatherby kill that a 338 WM can't?

"What can a 340 Weatherby kill that a 338 WM can't?"



You could just as easily turn that one around and say what can a .338 do that a .340 can't do easier ? The .340 could be more interesting to someone who is looking for the best internal and external ballistics . After all , as one guy's byline states ; this stuff is just for fun .

As to the notion that the Weatherby freebore and shoulder design will be killers for sporting rifle accuracy , I think the many enthusiastic fans of the .300 Weatherby cartridge would call hogwash on that one.....

quote:

What can a 340 Weatherby kill that a 338 WM can't?

What can a 300winmag kill that a 30-06 can't?

What can a 30-06 kill that a 308win can't?

What can a 308win kill that a 300 savage can't?

What can a 300 savage kill that a 30-30 can't?

and so on and so on and so on.

Or why not build a 338 RUM? A bit better overall accuracy and marginally better performance than the Weatherby.

This stuff never ends!

Where are the facts to support the RUM is more accurate than the 340 Weatherby? jorge

quote:

Originally posted by stubblejumper:

quote:

What can a 340 Weatherby kill that a 338 WM can't?

What can a 300winmag kill that a 30-06 can't?

What can a 30-06 kill that a 308win can't?

What can a 308win kill that a 300 savage can't?

What can a 300 savage kill that a 30-30 can't?

and so on and so on and so on.

My point is not that the 340 is a "bad " cartridge.Just deminished returns in turning
a 338 to a 340.It seems like alot of work ie $$$
And the difference between the two,to an elk,
just isn't worth the extra jingle,to me.
If thats the flavor you want,start with one.

McCray
The .338 RUM is an another choice that i would
look at but I am want to keep it on the model 70 in a somewhat classic caliber.
I have shot the .338 RUM and I can say it is here to stay.That was one of Remingtons better Ideas.
Just want a particular combo is all.
If I decide not to do this project I will either stay with the .338 win in a Winchester
classic action or buy a model 700 in a RUM
But I am a much bigger fan of the old school
Model 70.

I can understand that. I have two factory 338 RUMs, but when I built the 340 I used a winny.

Besides, back to the original gist of the thread, I have no idea what it would take to make a RUM feed in a 70.

Good luck with whatever you choose.