Barrel Swap between Mauser and M70 Win

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Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 7:55 am

Ok so I'm in thinking mode. Doesn't happen that often. As you may well know I have a M70 win and a MkX Mauser the MkX is a .308 and the M70 is a .22-250 I have been considering a .338 Fed on the M70 action but have decided I don't gain enough with a .338F when I already have a .308 hence My dilemma since I can only go short action cartridges on my M70. So I figured theoretically I could swap the barrel off the Mauser over to the M70 win and re barrel the Mauser in something like the .35 WHELEN or 9.3x62 since it is a Standard length Mauser Action.

Would this work or is it too hard to do?
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 22 Oct 2016, 10:44 am

No idea!
Any specs available on the barrel tenons of each action?

From my understanding if all comes down to the dimensions of the tenon and know forms. Are they the same diameter & length or close? Are they the same thread? Is the a kind enough Knox form for a setback and rechamber and a new tenon? Etc....
Last edited by Gwion on 22 Oct 2016, 10:48 am, edited 1 time in total.
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 10:47 am

I guess I'll go see doctor google about the barrel tenons
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 22 Oct 2016, 10:49 am

Yep doctor Google knows all! ;)
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Re: Barrel Swap between Mauser and M70 Win

Post by bladeracer » 22 Oct 2016, 11:17 am

One of the Ruger Compact Magnums maybe? They're for short actions and the RCM's both give about 200-300fps over the .308 and .338 Federal. The .300RCM is supposed to give you short-action .300 WinMag performance, The .338 RCM doesn't quite match .338 WinMag, but it goes close.

Case head is the same size as the WinMag's so you can maybe just swap in an M70 magnum bolt.
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 11:40 am

M70 tenon is 1"x 16tpi and .740 long
98M is 1.10" x 12tpi so in theory could machine the tenon back to 1" cut the threads and get headspace correct which may require trimming and recutting the chamber. Might be more pain than it's worth since I'd need the open sights to be square with the top of the rifle. Might ring my smith.
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 11:53 am

bladeracer wrote:One of the Ruger Compact Magnums maybe? They're for short actions and the RCM's both give about 200-300fps over the .308 and .338 Federal. The .300RCM is supposed to give you short-action .300 WinMag performance, The .338 RCM doesn't quite match .338 WinMag, but it goes close.

Case head is the same size as the WinMag's so you can maybe just swap in an M70 magnum bolt.


This is possible but I'd have to change the mag well and follower and the bolt then a new barrel getting very close to a new rifle $$ now.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 22 Oct 2016, 12:27 pm

Sounds theoretically doable. But what about you other barrel.... Is there enough left in the knoxfor for it to be refit to the M70?
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 1:43 pm

Gwion wrote:Sounds theoretically doable. But what about you other barrel.... Is there enough left in the knoxfor for it to be refit to the M70?


Knoxfor? Sorry is that a typo if not explain? Cheers. The barrel has plenty of life anyhow probably only has 5-600 rounds through it.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 22 Oct 2016, 2:12 pm

Yep typo. Knox form.

The bit of the barrel ahead of the tenon before the taper begins on a profiled barrel.
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Re: Barrel Swap between Mauser and M70 Win

Post by bladeracer » 22 Oct 2016, 3:08 pm

MalleeFarmer wrote:This is possible but I'd have to change the mag well and follower and the bolt then a new barrel getting very close to a new rifle $$ now.


I was figuring if you were happy to swap one barrel to another action on top of rebarreling the first action, you were determined to throw money at it anyway :-)

To recap:
You have a long action .308 Mauser and a short action .22-250 Winchester, both with the .308 bolt face.

You want to keep the .308.
But you also want something more potent than the .308. Do you want close range energy or long range accuracy?

I can see you've already put some research into this, and since the weather is atrocious you grabbed my interest.
Baseline .308 gives you a 200gn bullet at 2400fps.

One way is to rebarrel the short action to something bigger than .308 but keeping within the short action, and ideally the .308 0.473" bolt face. In proper rifle cartridges you're probably not going to get much better than .338 Federal for a ten-percent heavier bullet at similar velocity. .458 SOCOM is the heaviest bullet I can find, but in a Mauser action you can probably push a 250gn bullet at similar velocity to the .308 200gn. With the option of bullets up to 500gns at lower velocities.
Cost - a new barrel, threading, chambering, install barrel and sights, plus dies and brass.

If a magnum 0.532" bolt face is as easy as a bolt swap, that opens up your choices a bit more, although with some restriction on the heavier bullets due to the action length.
Cost - the above plus a replacement bolt?

The second is to swap the .308 barrel to the short action, re-thread, rechamber, install and reinstall the sights. For that much effort and expense I'd be inclined to go with a new barrel in something more useful than the .308, 7mm-08, 6.5x55mm or something similar.

Then rebarrel the long action to one of the .308 bolt face cartridges, of which .35 Whelen would be my choice. 8x57mm or 9x57mm are also good, but all are likely to have limited bullet choices.

Cost - a new barrel plus thread/chamber/install both barrels, install sights on two barrels, plus dies and brass.

Both of the above modifications have potential for problems with feeding, restrictions on bullet length and such.

The third option is likely to be the easiest and cheapest - sell the .22-250 and buy something else that does exactly what you're after.

Cost - potentially no cost at all depending on your sell/buy prices, but more likely a few hundred plus dies and brass.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 22 Oct 2016, 4:26 pm

Cost me about $1500 last year to do the same sort of thing but that included a stock and action. A good barrel and fitting/truing two actions should come in somewhere around the grand.

For my $1500 I ended up with a left hand pest control 223 and a right hand heavy varmint/target 7-08.
To me, that was good going as I'd have to have sold one rifle and replace it with two at about $3k.
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 22 Oct 2016, 9:18 pm

bladeracer wrote:To recap:
You have a long action .308 Mauser and a short action .22-250 Winchester, both with the .308 bolt face.

You want to keep the .308.
But you also want something more potent than the .308. Do you want close range energy or long range accuracy?

I can see you've already put some research into this, and since the weather is atrocious you grabbed my interest.
Baseline .308 gives you a 200gn bullet at 2400fps.

One way is to rebarrel the short action to something bigger than .308 but keeping within the short action, and ideally the .308 0.473" bolt face. In proper rifle cartridges you're probably not going to get much better than .338 Federal for a ten-percent heavier bullet at similar velocity. .458 SOCOM is the heaviest bullet I can find, but in a Mauser action you can probably push a 250gn bullet at similar velocity to the .308 200gn. With the option of bullets up to 500gns at lower velocities.
Cost - a new barrel, threading, chambering, install barrel and sights, plus dies and brass.

If a magnum 0.532" bolt face is as easy as a bolt swap, that opens up your choices a bit more, although with some restriction on the heavier bullets due to the action length.
Cost - the above plus a replacement bolt?

The second is to swap the .308 barrel to the short action, re-thread, rechamber, install and reinstall the sights. For that much effort and expense I'd be inclined to go with a new barrel in something more useful than the .308, 7mm-08, 6.5x55mm or something similar.

Then rebarrel the long action to one of the .308 bolt face cartridges, of which .35 Whelen would be my choice. 8x57mm or 9x57mm are also good, but all are likely to have limited bullet choices.

Cost - a new barrel plus thread/chamber/install both barrels, install sights on two barrels, plus dies and brass.

Both of the above modifications have potential for problems with feeding, restrictions on bullet length and such.

The third option is likely to be the easiest and cheapest - sell the .22-250 and buy something else that does exactly what you're after.

Cost - potentially no cost at all depending on your sell/buy prices, but more likely a few hundred plus dies and brass.


I'm still leaning toward the second option and would probably no worry about sights and just go with a 1-4 or 1.5-6x scope on the Mauser with a rebarrel in .35 WHELEN and have the M70 set up with the existing open sights on the Mauser barrel. Either that or keep them both and just buy a Zastava 9.3x62.

Gwion. The Mauser has already been trued and the barrel is a 1-12 krieger no5 contour so the m70 would be the only action in need of truing. Main reason for the querie is the M70 doesn't shoot worth a $#!+ and I would like another bigger cal since I built my 6slr varminter.
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Re: Barrel Swap between Mauser and M70 Win

Post by bladeracer » 22 Oct 2016, 9:39 pm

MalleeFarmer wrote:I'm still leaning toward the second option and would probably no worry about sights and just go with a 1-4 or 1.5-6x scope on the Mauser with a rebarrel in .35 WHELEN and have the M70 set up with the existing open sights on the Mauser barrel. Either that or keep them both and just buy a Zastava 9.3x62.

Gwion. The Mauser has already been trued and the barrel is a 1-12 krieger no5 contour so the m70 would be the only action in need of truing. Main reason for the querie is the M70 doesn't shoot worth a $#!+ and I would like another bigger cal since I built my 6slr varminter.



I'd be very surprised if anybody is willing to even try to thread a barrel to an action with any likelyhood of keeping pre-installed sights perfectly vertical.
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Re: Barrel Swap between Mauser and M70 Win

Post by MalleeFarmer » 23 Oct 2016, 7:55 am

bladeracer wrote:I'd be very surprised if anybody is willing to even try to thread a barrel to an action with any likelyhood of keeping pre-installed sights perfectly vertical.


This was my main concern.
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Re: Barrel Swap between Mauser and M70 Win

Post by straightshooter » 12 Jan 2017, 7:38 am

bladeracer wrote:
MalleeFarmer wrote:I'm still leaning toward the second option and would probably no worry about sights and just go with a 1-4 or 1.5-6x scope on the Mauser with a rebarrel in .35 WHELEN and have the M70 set up with the existing open sights on the Mauser barrel. Either that or keep them both and just buy a Zastava 9.3x62.

Gwion. The Mauser has already been trued and the barrel is a 1-12 krieger no5 contour so the m70 would be the only action in need of truing. Main reason for the querie is the M70 doesn't shoot worth a $#!+ and I would like another bigger cal since I built my 6slr varminter.



I'd be very surprised if anybody is willing to even try to thread a barrel to an action with any likelyhood of keeping pre-installed sights perfectly vertical.


Bladeracer, The last option you mention is probably the wisest and cheapest way out for you. Just as it is also a good idea to stick with cartridges based on 30-06 or 8x57 sized cases for good feeding and best magazine capacity in a M98.

Gwion, Any competent gunsmith can do the job you refer to. They might not want to do it because of the time and effort required to do it correctly and then have the client baulk at the costs involved.

Other posters talking about a Knox Form.
Do you know what you are talking about?
It seems to be fairly commonplace to see references to a knox form when talking about most rifles these days but its usage is all wrong. In this thread neither the M70 or M98 will have a knox form.
Where will one see a knox form? Have a look at the chamber reinforce of a 303 or Martini. That flat area with some of the chamber reinforce machined off is in fact the knox form.
What is it used for?
It was devised by a gunsmith named Nock in the early 19th century to simplify the fitting up of barrels so the sights finish in the correct position in relation to the receiver.
This is one of those cases where trying to sound knowledgeable does the exact opposite.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 13 Jan 2017, 7:10 am

And that is a classic example of someone trying to sound superior rather than constructively contribute to a discussion. We can all use google and regurgitate technical info.

what ever the origins of the term, "Knox form" is common parlance for the parallel section of barrel immediately forward of the barrel tenon and preceding the beginning of the taper.
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Re: Barrel Swap between Mauser and M70 Win

Post by straightshooter » 13 Jan 2017, 9:45 pm

Gwion wrote:And that is a classic example of someone trying to sound superior rather than constructively contribute to a discussion. We can all use google and regurgitate technical info.


Yes but I suppose it helps if you have some idea what you are talking about so you actually know what to google. And then when you have googled your topic how do you establish that what you have read has been posted by a knowledgeable or opinionated person. Why would I bother with google if I have already read the textbook?

Gwion wrote:what ever the origins of the term, "Knox form" is common parlance for the parallel section of barrel immediately forward of the barrel tenon and preceding the beginning of the taper.


Yes but 'common parlance' among whom.

I suppose for some, when you have nothing else, then go ad hominem.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 13 Jan 2017, 10:44 pm

Two questions, then, seeing your knowledge is so far superior anyone else here:

1/ what do You call the parallel bit of the barrel commonly referred to as the Knox form?

2/ What exactly, other than asserting your superior collection of books, did your previous post constructively add to the discussion that warranted dredging it up almost 3 months after the last post was made???
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Re: Barrel Swap between Mauser and M70 Win

Post by straightshooter » 14 Jan 2017, 7:46 am

Gwion
First an apology.
I have just reread my initial post and now realise I got a little confused with attribution of comments to the posters indicated in the quote.
My first comment should have referenced Malleefarmer.
My second comment should have referenced Bladeracer and not you.
The third comment was not directed at anybody specific.
Again my apologies to all.

As for your last post,
1/ In my experience, the commonly used term for the actual piece of barrel metal you refer to is a chamber reinforce. Knox form is a hand me down term inherited mainly from Lee Enfield armourers and I suppose by now you will have googled it to your satisfaction. When terminology is misused what is that telling you about the speaker?
2/ I don't do many posts on these forums and generally look for something interesting to read over breakfast, irrespective of how long ago it may have originally been posted, and if I think I can contribute something informative then I try, sometimes I hope successfully. I generally avoid the "what direction is my arse pointing" questions and leave them to the google an answer and then post types who often do an adequate job.
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Re: Barrel Swap between Mauser and M70 Win

Post by Gwion » 15 Jan 2017, 11:57 am

Ok.
You just may get more engagement if you're not coming across as if you are just looking to trip everyone up on small technical trivialities.

In response to your previous post. A good gunsmith will point out the difficulties and costs involved and suggest other options for the client to make an informed decision as to how to proceed with a project.
If your gunsmith won't engage at that level then find one who will.
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