I have an m70 Win in 300Win that I'm not using. I have a 375. So I'd like recommendations on a .416 or larger that will feed well in a long action controlled round feed post 90's M70 action. Also a smith to do the work.

a 300 win is a 3.35 length round - all of the accurate reloading rounds are that length .. the 416 (don't do it.. just do a 416 ruger) the 458 accrel is just a barrel away from a VERY affordable bigbore .. then the 470 .. all of these use .532 bolt faces, same as your 300 win

Do you want a factory chambering or wildcat? And how many dollars will you devote to the project?
458 win mag or 416 Taylor (the best)are just a barrel swap. Add feed rail and maybe mag box fixes and you get the AccRel's, B&M's, 416 Rem, 458 Lott, 404 Jeff. 458 Win is simple, easy and lots of horsepower. Don't forget appropriate stock work (bedding and bolts) for increased recoil. 416 Ruger is an option.

The advice looks sound.

Either a 416 Ruger (easiest barrel switch and access to components)
or a 458 AccRel (slightly more capacity than Lott, 6.1 grains).

It probably depends on what you will use it for? Elk + bear, or cape buffalo? For elk, you will want the flatest configuration, for buffalo, the fattest.

PS: In terms of overall expense, I would consider buying a used Ruger 416 Ruger, either 23" African model or 20" Alaskan. They are both great hunting rifles and can be found at not much more than a rebarreling and chambering job. Then if you still want a rebarreling project think about a wildcat or something that justifies the need for rebarreling, possibly based on opening up the bolt-face to .590" (The Lapua and Rigby casehead).

PPS: McGowen Barrels did my 500 AccRel Nyati and can probably handle the 458 AccRel easily for both the barrel and chambering. Give them an email. I'd guess around $700-$800, including iron sights.

quote:

I have an m70 Win in 300Win that I'm not using.

Yep, I know the feeling. When Winchester closed the New Haven facility I was buying a lot of M70s to use for conversions to real guns. I ended up with a dozen or so different 300s, 7mms, 338s, having a vision to convert to something worthy.

That was a vision I tell you! We ended up using 6 of these to make 458 Lotts. And talk about a BITCH. All required way way more work than first thought to make them RELIABLE. Retaining cartridges in the magazine is a major issue! And then getting them to feed proper is an issue, when you get one thing solved, the other comes to play and is a problem. During those years Winchester farmed out magazine boxes, floor metal, and so forth, and we had 6 guns with nearly as many differences in magazine boxes and floor metal. Hard to get the right parts to make them into 458 Lott to begin with, and even when you thought you had it, another issue comes up. Going from 300 Win to any longer cartridge in a M70 is not something easily done.

Sam is running into that exact same issue right now converting a M70 in 300 to a 458 Lott for one of his PH's....... Last week I sent him home with my Factory Custom Shop 458 Lott to compare parts and even try my parts in his gun.... No Go... No Joy!

I am convinced that MAYBE you could convert to a 458 Winchester, or 416 Tayler, as Dan says, but going to longer, get ready to be frustrated.

I am a bitch when it comes to 100% reliability. I WILL NOT ACCEPT LESS....... To even consider converting one of these standard action M70s to a RUM based case, AR or B&M is even more folly, it cannot ever be done and be done 100% Reliable. 99.99% of all work I have done is by SSK Industries, and they are very very good at most anything. However, Brian and I talked extensively and looked at these same actions to use on some of the B&Ms, as well as 500 MDM.... Brian said no, that there was no guarantee that you could ever get one to work properly. I then found a lot of the basic, no head stamp Ruger brass a few years ago. Little smaller in diameter than the RUM.... Looked like it would work to me, I was fairly convinced of it. Sent this up to Brian, same story, no go, no promise it could work, no matter how much time spent..... OK, then another well known very good gunsmith said he could do it, no problem. OK, lets find out. Sent rifle, dummy samples, brass, the works. 2-3 months later, exactly the same story, no guarantee that you could ever spend enough time on it to be worth it, and get 100% reliability.... The major issue is RETAINING CARTRIDGES in the magazine, as the bolt is taken back. Not much good to have 3 rounds down, and as the bolt comes back, they spill out of the top on the ground.........

For this reason on all the B&Ms we use WSM actions. For the 500 MDMs we use the RUM action, which has been very modified to run the RUM cases.

I am not sure of this, but I think if you are dead set on converting, you might be far ahead going with a shorter 458 Winchester, or like Dan says, 416 Taylor.......

Good luck.....

Michael

Another guy who has tried to convert an M70 says that you can only get 2 rounds in the M70 mag. I'm going to drop that idea and order a Montana if I pursue this further. I may sell the M70, which is a lefty, by the way.

AS Michael said I've been working on a 458 Lott built from a 300 Win model 70 action. Mag box plenty long enongh same as factory Lott once spacer is removed. The real issue is getting it to retain cartridges in mag. Feeding is slick but sometimes the round under the bolt wants to pop out as bolt is retracted. Not good for a dangerous game backup gun. It has to be 100% reliable!!! I found that the rail opening and mag box are much narrower in factory Lott than the 300 Win mag. You would think it would be wider. I guess Winchester went through all those feeding issue too before they figured it out. The Lott has been the most frustrating build I've ever done and it will be my last Lott for sure. I think any of the standard length big bores or the 375 H&H will work fine for converting too. More power to you if you do a Lott.

Sell the .300 and buy a new Model 70 in .375 H&H. Cheaper and will work better in the long run.

Had the same problem and went with the 416 Taylor and no problems feeding or anything else..Good luck with your project.

No lefty M70s any more. Montana 1999 may be it.

quote:

Originally posted by Vol717:
No lefty M70s any more. Montana 1999 may be it.

Yes, Montana looks nice. Your main concern will be to decide which calibre and then which action. Personally, I would only order the big PH action if using a Rigby case or larger. For something like a 416 Ruger or 458 Lott, you would want the standard Montana. And yes, my wife and I thought about the Montana for her 'leftie'. The Ruger Hawkeye was simply more easily available and at a very good price. Her calibre choice was only a 375 Ruger anyway, so she didn't need something truly big.

The easiest and least expensive conversion is the .416 Chatfield-Taylor, its easy to make feed 110%, its an accurate round and more than suitably for any of the big 5, now big 4 as we must delete the Black Rhino these days. A 416 Remington is another option, but a bit more work. both are good options. I suspect your present barrel is good for a rebore to .416 and that saves some bucks, and these rebored barrels today seem to shoot damn well...I use High Plains Reboring and every barrel I have done shot at least and inch and some better..

How about the .425 Express? It is the .300 Win mag necked up to take .423 bullets. It gives 2400 fps with 400 grain bullets.