Jump to content
Military Firearm Restoration Corner

7Mm-08 To 7X57


rwims

Recommended Posts

I have recently acquired a 7mm-08 Remington barrel and plan on rethreading for a Turk action. I would prefer to re-chamber to a 7x57 if possible. I know even if I stay with the 7mm-08 I will have to deepen the chamber. Would it be enough to allow for the 7x57 ?

Link to comment
Share on other sites

The 08 case is considerably larger diameter at the shoulder than the 7x57 at same forward location from base. Barrel would require setting back quite a bit to do away with original 08 shoulder. Whether this could be done and still leave enough meat to support the chamber area would depend on contour of barrel in question.

 

JM2c

Link to comment
Share on other sites

[EDITED 2X]

 

The 7-08 has a shoulder diameter of .454 at 1.560.

 

The 7X57 has a shoulder diameter of .430 at 1.730, body taper 0.7823 degrees.

 

(0.454 - 0.430) / 2 = 0.012 (half the diameters to establish the opposite side of our triangle)

 

x = (0.012) / (tan 0.7823) = 0.879 (distance down the 7X57 taper to get to a 0.454 diameter)

 

1.730 - 0.879 = 0.851 inches (base to 0.454 diamter on 7X57 case)

 

1.560 - 0.851 = 0.709 inches (deeper to 7X57 0.454 diameter)

 

0.709 X (16 threads/inch) = 11.34 threads

 

So, at an absolute minimum, you'll have to take at least 0.709 off the end to clean out the shoulder of the 7-08 chamber. That's assuming an absolute minimum dimension 7-08 chamber.

 

That will be 11.34 threads, or 12 full threads ( or 0.750) with open sights on the barrel.

 

Is my math right now?

Link to comment
Share on other sites

  • 1 month later...

do you feel confident that it would clean up a 7mm-08 with a 7mm-mauser imp I ask because I would like to do a handi-rifle barrel and what headspace gauges would you use ? could this be done with a hand reamer hate to waste a barrel trying this but I like doing things differant

Link to comment
Share on other sites

do you feel confident that it would clean up a 7mm-08 with a 7mm-mauser imp I ask because I would like to do a handi-rifle barrel and what headspace gauges would you use ? could this be done with a hand reamer hate to waste a barrel trying this but I like doing things differant

http://www.shootersforum.com/451407-post5.html

 

According to this site it can. I have little doubt that it will.

 

With the cost of custom dies and reamers, why not just go with the ,284 Win? Capacity between the 7x57 AI and .284 Win should be very close, and the .284 should be cheaper to build.

Link to comment
Share on other sites

http://www.shootersforum.com/451407-post5.html

 

According to this site it can. I have little doubt that it will.

 

With the cost of custom dies and reamers, why not just go with the ,284 Win? Capacity between the 7x57 AI and .284 Win should be very close, and the .284 should be cheaper to build.

 

I can see one obvious reason. Probably same one that precludes H&R from offering the .284 in a Handi. The 284 is a rebated extractor rim cartridge. So no problemo with a bolt gun because the extractor grasps the case from the rear. But a Handi extractor hooks the case from the bottom. So if chambered in 284 the extractor would extend upwards past the chamber wall.

Link to comment
Share on other sites

it's really not a performance thing or money thing because they offer the .280 remington in the barrel accessory program for 120.00 dollars and that's as cheap as it comes . I just like the old mauser rounds and this would be different also wildcats have low resale value but sometimes you just need a little excitement

Link to comment
Share on other sites

the barrel accessory program is you buy a rifle and then you can send the receiver back to H&R or nef actually the same company and they will install a new barrel in your choice of calibers that they offer and since they are single shot rifles they can interchange in less than a minute so you can have anything from .500 s&w to .22 hornet I personally bought a .308 for my wife and it kicked a little much so I handloaded it down but later bought her a 30-30 winchester barrel and then a .22 hornet and now I'am wanting a 7x57 imp all on the same gun the trick is to send the gun back and get all the barrels you want so to save on shipping this time I will also get a 28 gauge shotgun barrel they are really cheap and I've never owned a 28. The only thing is that a rifle receiver can accept a rifle round and shotgun shell but a shotgun cannot accept a rifle cartridge the receivers are stronger in the rifle. I like them and they are very safe for someone to learn with you cannot forget the safety or mistake the gun for being loaded just open it and verify an empty chamber very simple. They are light, short, cheap, and accurate what more can I say I like them.

Link to comment
Share on other sites

  • 2 weeks later...

do you feel confident that it would clean up a 7mm-08 with a 7mm-mauser imp I ask because I would like to do a handi-rifle barrel and what headspace gauges would you use ? could this be done with a hand reamer hate to waste a barrel trying this but I like doing things differant

 

It will clean up. You have two choices to get to 7x57 AI on a handi/nef. Rechamber a 7mm-08 barrel or get a 22-250 barrel and send it off for rebore and rechamber. There are a couple of reamer rental sites that can assist you in reamer and guage selection. They will also let you know if it is a DIY hand reaming job or you need to have it machined. Either way it is an investment well beyond what you will have in the original rifle.I have seen charts where the 6.5x55 and 7x57 mauser cartridges are one of the top "gainers" for velocity if you AI them. Grated the increase in velocity is not always an indicator on overall perfomance and accuracy, but it is a gain.

 

I researched at length this very route and went the 22-250 barreled action route and had it rebored and re-chambered in 8x57 mauser by a smith to compliment my sported German BCD 43. They are my travel hog/deer rifles. The mauser for the primary and my HR/NEF as a backup with one ammo in a double case.

 

Of course, there are plenty of chopped up mausers out there in 8x57 and 7x57 just begging to be given a new life and Ackley Improved...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...