Re-barrel 6.5x55 to 7.5x55

jeanlikethis

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Hi,

would it be possible to re-barrel a Swedish M96 (6.5x55) to Swiss GP11 (7.5x55) after the bore is shoot out.

I checked the rounds pressure and 6.5x55 and 7.5x55 are very close. Would this mean we can turn old M96 into new GP11 boy.
 
i sold my 6.5x55 before doing it, but i know Tradex, a banner sponsor has NOS actual barrels in the white. So actual threaded 6.5x55 barrels in the white or not blued, packed in grease for 70+years...for $100.

Much cheaper, if that is a issue and one has a chance of finding ammo/projectile. Just in case you are like me and overthinking things. Simple and cheap versus a project...MEH
 
i sold my 6.5x55 before doing it, but i know Tradex, a banner sponsor has NOS actual barrels in the white. So actual threaded 6.5x55 barrels in the white or not blued, packed in grease for 70+years...for $100.

Much cheaper, if that is a issue and one has a chance of finding ammo/projectile. Just in case you are like me and overthinking things. Simple and cheap versus a project...MEH

Trade-Ex sold out of those NOS M38 6.5x55mm barrels awhile ago, and they said they do not expect to see anymore again.

You will have feed issues if you rebarrel to 7.5x55mm unless to modify the receiver. Also it is much easier and cheaper to keep it 6.5x55mm as the factory ammo is far more available and cheaper too than 7.5x55mm.

Just buy a K31 while you still can from a site sponsor like CSC for $250 if you want a 7.5x55mm rifle that feeds well and is designed to perform right for that round. It will cost you more to alter the Swedish Mauser and most typically frown upon people altering Milsurp rifles on this forum!
 
Are there still milisurp 6.5x55 rounds left. I know many sponsors have GP11 milisurp. Never saw a 6.5x55 other than factory ammo, like PPU, etc.

Maybe it is better to trade the old rifle before it is shoot out. Might also need to back more than one for each caliber.
 
Handloading is your best option.

The 6.5x55 is one of the most highly-developed long-range cartridges ever produced and it is very easy to load your own and obtain excellent accuracy at a reasonable price.

I have been shooting 6.5x55 for the last 30 years, so far, and I have bought exactly TWO boxes of factory rounds; everything else has been handloads.

Accuracy? Used to get 1.5 MOA in one Mauser, half a minute in the other. Not any longer, but the problem is my ancient eyes, not the rifles...... which happen to be considerable older.

You can set up with a basic outfit for about the price of 7 or 8 boxes of ammo and it will last you a lifetime. I am still using the equipment I bought in 1966.
 
Maybe it is better to trade the old rifle before it is shoot out.

You seem to see rifles as if they were cars. They are not. As it has already been said, the rifle will last you a lifetime, if you just put a dash of oil on it from time to time. Heck, look at all the Mauser 71s, and the Sniders... they still shoot great.
 
Thank you all for all above.

I love those SW (Swiss and Swedish) rifles, their military issued rifles are ranked as matching accuracy piece of art.

All my vintages rifles are in good conditions and I just want to find a way of keeping them after their possible shoot out.
 
If you want to re-barrel it to a new caliber, 308 would be the one to go to. Ammo is cheaper and available and lot of barrels around.

I did one and it works very well. lots of them were converted to 7.62x51 for target shooting. They feed perfectly.
 
If you want to re-barrel it to a new caliber, 308 would be the one to go to. Ammo is cheaper and available and lot of barrels around.

I did one and it works very well. lots of them were converted to 7.62x51 for target shooting. They feed perfectly.

7.62 NATO rounds has the psi of ~67500 and .308 has 62000. 6.5x55 only has ~55100. Would it be safe to do that? 7.5x55 has the psi of 55000, that is pretty close to 6.5x55.
 
7.62 NATO rounds has the psi of ~67500 and .308 has 62000. 6.5x55 only has ~55100. Would it be safe to do that? 7.5x55 has the psi of 55000, that is pretty close to 6.5x55.

NATO and 308 have almost identical pressure limits. the apparent difference is because of different measuring systems. (like miles and kilos).

But 6.5 is less pressure. that does not mean the rifle will not handle the 308 or 7.72. As I said, many M96s were made into target rifles in 7.62. They were called "Carl Gustafs" and were favoured for long range shooting.
 
I needed a pre 1912 rifle for a military rifle competition in the US, so I bought a Mauser M96, due to problems getting my 1903 Springfield across the border. The kicker is that I needed lead bullets, match requirement, so I ordered a 150 grain 6.5x55 mm bullet mold from Buffalo Arms Co. (they export to Canada). My M96 now has over 200 gas checked lead bullets through it with absolutely no wear on the barrel. I personally don't cast, but I have friends that do. My Mauser barrel should last another 114 years at minimum!
 
Should you ever happen to "shoot out" an M96 or K31, at present, it would be far far cheaper to simply replace it with another. The necessary gunsmithing work plus parts needed to do a caliber change would cost much more.
 
OP, there's good advice on here that you should listen to.

Here's my experience with "shooting out bores". As friends of mine like Smellie can attest I shoot a lot, pretty much weekly in the summer. I put more rounds down the pipe of my Milsurp rifles in one month then most guys do in several years. I've yet to "shoot out" or wear any of my rifles. The problem is most shooters today have no idea that old millitary rifles were made with quality and therefore would hold up to 10's of thousands of rounds and still not wear out. Unlike today's modern overpressured boat tailed calibers that turn a new bore into a smooth bore often in 4 or 5 thousand rounds.

Now as to rebarreling a swede to a Swiss I'm of the belief that anything is doable but the cost of the conversion would cost you a small fortune. It would be WAY cheaper to just buy a second swede and keep on shooting.

If you are going to shoot obsolete or old calibers then spending the money to set up for handloading is the best option. Surplus rounds are going go run out, it's only a matter of time. 10 years ago you could still buy 8x57, 303 and other famous military cartridges but now all of that has been sold and is pretty much impossible to find in any quantity.

Lastly I do own a Swiss k11 that is rebarrelled to 6.5x55 and the amount of work that some one did to make it feed and fire is amazing. Would cost 1000's to do the same conversion today. I'd say that putting a Swiss barrel on a swede would be just as involved of a job.

Shoot your rifle lots and give her a good scrubbing once in awhile and it will last you another 100 years. If they wore out as fast as some people think then it would be easy to say that all surplus guns should be shot out by now wouldn't it?
 
The MAIN difference between the two cartridges devolves around the volume of the cases. A sectioned 7.62x51 case will show rounded internal base, giving a much stronger lower section to the case. This is because the round was designed from the get-go as being used in a semi or fully automatic fiream of one kind or another, and having the bottom of a case pulled off by hard extraction in a machine gun is not a good way to put down fire. By comparison, the .308Win case has a much flatter internal shape - leading to an increase in case volume by up to 10% over that of the NATO case.

This CAN lead to higher pressures being generated in the .308Win cartridge.

Just as a matter of interest, here in UK the two Proof Houses - Birmingham and London - set different standards for the two cartridges, and stamp the proofed firearms accordingly. Both of these are taken from two rifles I shoot regularly, BTW, so I'm not blowing hot air here -

Schultz & Larsen 300m match rifle - 7.62x51 NATO 19 TONS PER INCH [SQUARE SYMBOL]

Gruenig & Elmiger match rifle - .308WIN 20 TONS PER INCH [SQUARE SYMBOL]

My .308Win Krico 650SS was made in Germany and is therefore exempt UK proof as Germany is one of the fourteen or so CIP nations.

So, if there was no difference, then it is axiomatic that the figures would be identical.

tac
 
old millitary rifles were made with quality and therefore would hold up to 10's of thousands of rounds and still not wear out. Unlike today's modern overpressured boat tailed calibers that turn a new bore into a smooth bore often in 4 or 5 thousand rounds.

Thanks for the talking. I believe the lower pressure and the slower muzzle speed might also contribute to the long lasting bore life. Might be the same reason 22lr barrel last for generations. I got a carbine version Ruger 10/22 and one day I found a stainless steel standard barrel in one gunsmith store that priced $50. I asked the guy how the bore condition is and he told me he never saw any worn out bore on 22lr. So I picked the barrel and replaced my short carbine barrel. It shots pretty well.

Also bolt action might also lead to slower fire rate and preserved the bore. Not like modern auto/semi-auto rifles that fire the rounds in 1 min that old bolt action will take one week to consume.

One thing concerns me is that the dry out of the surplus ammo. There are 6.5x55 and 7.5x55 commercial rounds available but not sure if they are going to keep on the production. I believe 6.5x55 are very popular in Europe that people use for hunting and targeting. But for 7.5x55, it might hard to say. Reloading is the good way to go. Need to start collect the brass from now.
 
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Unless you are doing competitive shooting, you are not going to wear out your bore enough to notice the difference between a 6.51 and a 6.55 bore. Also, if you want a 7.5x55 buy a Schmidt-Rubin.

That being said, if you feel your rifle is "shot out" sell it to a collector and get another one. You will pay much much more to rebarrel the rifle to another caliber than the project is worth compared to buying another complete rifle in a caliber you desire.
 
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