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Build question

 
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  #1  
Old 09-11-2010, 07:36 PM
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Build question

I have a Winchester Model-70 (ya I know ''who'd have guessed'') chambered in 300wby. I only have less than 100 rounds down the pipe, but for some reason I dont like it. So I looked up J E's post on bolt face diameters shown here;

Long actions with a bolt face .Dia of .540 +/-
264 Win Mag, 270 weatherby Mag, 7mm Rem Mag, 7mm Weatherby Mag, 7 STW,
7mm Rem Ultra Mag, 300 H & H, 300 Win Mag, 300 Weatherby Mag, 300 RUM, 303 Brit,
8mm Rem Mag, 338 Win Mag, 340 Weatherby Mag, 338 RUM, 375 H & H, 375 Weatherby,
375 RUM, 416 Rem Mag, 458 Win Mag, and the 458 Lott.

Now my questions are;
1. Can I turn my Model-70 into a 338RUM?-same bolt face, and c.o.a.l. of .04 more than the 300wby, or is that .04 longer c.o.a.l. not gonna jive with my action.
2.Would a 338 RUM with a 28'' pipe be near the Edge for velocity? I dont want to monkey with brass necking up a 300RUM into 338 edge. and bother with custom dies etc.
3.Would there be any forseeable problembs, such as needing new bottom metal, will the current action length be ok etc? Im not planning on shooting super long 300gr. Bergers. Probably 225gr, or 250gr Accubonds.
4. I love my Model-70's and unfortunately Winchester does not currently offer a 338RUM chambering, or I could just go that route. Heres my delima
I want a 300wsm and I have a 300wby
I want a 338RUM and I have 338WIN
Am I better off parting ways with both and getting the 300wsm, and wait and hope Winchester/FN comes out with a 338RUM offering sometime in the futre? Or should I sell the 338 and buy a 300wsm, and build my Model-70 300wby into a 338RUM-IF ITS POSSIBLE-?
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  #2  
Old 09-11-2010, 08:48 PM
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Re: Build question

Winmag, I may be able to help a little bit. I'm not familiar with the Mod 70 action, either pre '64 or post '64 push feed, but I'll share what I do know.

First, if it's a post '64, be sure the serial # has a G prefix. The ones without the G prefix I believe are investment castings. They made them during the transition. If it's a pre '64, they're all forged.
I wouldn't barrel up a RUM on a cast receiver. Just my opinion.

On the bolt face, the only thing I recommend is if the Winchester bolt has a recessed face like the Rem or Wby, turn a slight chamfer on the inside front corner of the lip to be sure you headspace on the base of the cartridge and not the bevel on the cartridge just in front of the extraction groove. I saw that happen on a Rem 700 bolt.

#1 question. If you are willing to single load, no problem. The cartridge OAL's you listed are probably maximum SAAMI OAL's and could be loaded short enough to fit in a .300 Wby length magazine, particularly with 200-225gr bullets.

#2 question. Given the same barrel length, the .338 RUM can't quite match the Edge performance, but it is so good that I could live with it easily.

#3 question. You may not need new bottom metal, but you will need a mag box and follower that will feed the fat RUM case. The .300 Wby is a staggered feed, and may not be able to be modified to feed the RUM cartridge. The right pieces are available for Rem 700's and Wby MK V's, but I don't know about the Mod 70.

The .338 Win Mag bolt face is a std belted mag bolt face and the .300 WSM has a .473 case head. It's not on JE's list. You would have to change bolts. Instead, look at the Rem .300 Short Action Ultra Mag (SAUM). It should work, and might feed out of the .338 Win magazine. I haven't done it, so I don't know.

#4 question. I will always spend money on a custom barrel instead of expecting a factory barrel to perform satisfactorily. My experience is that factory barrels only meet 1 moa about 25-30% of the time. A quality custom barrel such as a Lilja, Krieger, Hart, etc. will do it every time if the installation is done right. Also just my opinion.

Except for solving feeding problems, I think you can rebarrel your rifles to do what you want. If you know a 'smith who is building consistently accurate rifles, talk to him about your projects. There's an excellent chance that an experienced professional riflesmith can answer your questions definitively.

I hope that some more knowledgable members will jump in.

Good luck, Tom
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  #3  
Old 09-12-2010, 08:07 AM
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Re: Build question

Quote:
Originally Posted by winmag View Post
I have a Winchester Model-70 (ya I know ''who'd have guessed'') chambered in 300wby. I only have less than 100 rounds down the pipe, but for some reason I dont like it. So I looked up J E's post on bolt face diameters shown here;

Long actions with a bolt face .Dia of .540 +/-
264 Win Mag, 270 weatherby Mag, 7mm Rem Mag, 7mm Weatherby Mag, 7 STW,
7mm Rem Ultra Mag, 300 H & H, 300 Win Mag, 300 Weatherby Mag, 300 RUM, 303 Brit,
8mm Rem Mag, 338 Win Mag, 340 Weatherby Mag, 338 RUM, 375 H & H, 375 Weatherby,
375 RUM, 416 Rem Mag, 458 Win Mag, and the 458 Lott.

Now my questions are;
1. Can I turn my Model-70 into a 338RUM?-same bolt face, and c.o.a.l. of .04 more than the 300wby, or is that .04 longer c.o.a.l. not gonna jive with my action.
2.Would a 338 RUM with a 28'' pipe be near the Edge for velocity? I dont want to monkey with brass necking up a 300RUM into 338 edge. and bother with custom dies etc.
3.Would there be any forseeable problembs, such as needing new bottom metal, will the current action length be ok etc? Im not planning on shooting super long 300gr. Bergers. Probably 225gr, or 250gr Accubonds.
4. I love my Model-70's and unfortunately Winchester does not currently offer a 338RUM chambering, or I could just go that route. Heres my delima
I want a 300wsm and I have a 300wby
I want a 338RUM and I have 338WIN
Am I better off parting ways with both and getting the 300wsm, and wait and hope Winchester/FN comes out with a 338RUM offering sometime in the futre? Or should I sell the 338 and buy a 300wsm, and build my Model-70 300wby into a 338RUM-IF ITS POSSIBLE-?

After building quite a few guns over the last 12+ years this is what I've pretty much whittled this sort of question down to:

1. Is or can the bolt face be altered to physically retain the rim of the cartridge?
2. Is or can the action magazine well/feedlips be altered to facilitate loading?
3. Is the ejection port long enough and can it be lengthened if its too short?

If yes is the answer to all three then give it hell.


In your case:

If the action you have uses a "T slot" style extractor then it's going to be a bit tricky to open the bolt face. It's not as simple as a guy would like. There are a couple things that need to be addressed. This particular extractor runs via a hole that's drilled in the face of the lug. A spring/plunger goes into this hole. It then drives a cone shaped (generally) countersink that is in the extractor. Opening the bolt face for a larger cartridge means that the extractor must move away from the center of the bolt face in order to be able to purchase the case rim for extraction and to be able to snap over the rim of the case when loading. The snapping action comes from the extractor begin able to slide back and forth in the T slot.

If I was head set on doing this then I would probably attack it by machining a pin to fill the hole that the spring/plunger goes into. I'd then solder the pin in place with some low temp stuff (so as not to kill the heat treatment of the bolt lugs) and then relocate the hole. Chances are the extractor will need to either be made over or modified as the radius is different on the case/extractor.

That's a push feed style.

If it's a CRF (control round feed) then essentially the same basic process will need to take place, although it'll be a little different. The bolt face has to get bigger and the extractor needs to be refitted to make the thing work right.


IMHO a magnum type cartridge that does NOT use a belt around the case web is always more desirable than one with a belt. They just run easier and the gunsmith chambering the gun can take advantage of a true headspace dimension instead of just using the belt. (Although I personally have all my gauges made so that I take a true shoulder/case head length when chambering)

What I would NOT do under any circumstance:

Have a Sako style extractor installed. I am very opinionated on this for safety concerns. I have a cardinal rule regarding them; I will not install or service a Sako extractor installed on a twin lug, 90* turn bolt action that uses a full length raceway.

The reason is simple. The extractor isn't supported by anything when the bolt is in battery. If a case ruptures that little bastage will come flying out and if it hits a person it's very possible to kill or critically injure that person. I know of two cases this year alone that resulted in surgeries.

Hope this helped.

Chad
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  #4  
Old 09-12-2010, 09:01 AM
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Re: Build question

Thanks guys.
I appreciate the info.
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GOD,GUNS,&GUTTS MADE AMERICA, LETS KEEP ALL 3!winmag

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  #5  
Old 09-12-2010, 09:11 AM
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Re: Build question

My sediments about the Sako style extractor exactly! Have ya' priced that Winchester push feed extractor lately? Tom, I've re-barreled several .300 RSAUMs' to .300WSM. Same bolt face. The reason,,,, ammo/component availabilty.
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  #6  
Old 09-12-2010, 10:33 AM
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Join Date: Dec 2007
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Posts: 94
Re: Build question

Some good advise given already, but I'll offer my 2 cents. You already have a 300 Wby, so the bolt face is the same as the 338 RUM.You will need a new mag box and follower. It probably will be tough to find though they were made in 300RUM (same as the 338), problem is the feed rails may or may not work, necessitating some work. Get at least a #4 contour custom barrel and a good brake(Vais, DE, Muscle brake- ranging from unobtrusive to offensive and all LOUD). The contours of all barrels will be heavier than the Winchester and need to be, so you will need to open up your stock or replace with a good (Mcmillan, High Tech or Manners) stock. This has already added up to quite a sizable investment... So how much better than the Weatherby is it... For BIG longrange game it is a major step up in killing power for a carry gun- not into the league of the EDGE shooting 300gr bullets. Those are dedicated platforms and require the commitment to the discipline to master and use. If you go that route please go the whole way, it isn't just a rebarrel.
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  #7  
Old 09-12-2010, 02:03 PM
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Posts: 4,550
Re: Build question

Man, I can't believe I missed your thread man! If a man doesn't have something to launch a 300 Berger at an elk I think that should be priority #1

I had a guy ask me about tweeking on a Win Mod 70 chambered in a 270WBY and I got to looking around and an earlier Win factory chambered in a WBY can be a gold mine so I told the guy not to tweek it but buy another gun to work with!

I haven't measured up a Mod 70 for an RUM so I have no real advice there, I should measure up my dad's to see how it would fit. I would just roll with the 338RUM though, being just a tough shorter helps the feeding and there is hardly any practical difference between the RUM and EDGE.
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