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Military Firearm Restoration Corner

This Has Had To Have Been Done.


Ron J

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I'm going to tap the minds here. I have a Danzig small ring 98. Large ring threads and relief. I want to make it a 7x57 and hope it doesn't stretch. I've also got a take-off 7mm mag win mod 70 barrel. First I'll cut the chamber end off the barrel. Then turn down a few inches of the end and thread the O.D. maybe .750-16. Make a sleeve to go over it (.750-16 inside threads) to bring the chamber area & thread end back up to the front ring diameter. Will this hold together? I have access to pre-heat treated 4340 for the new sleeve. I figured that would be close to the win barrel strength.

If anyone has tried this, someone from this group has! My experience with metallurgy is limited to what I do and I have no idea what dynamics are taking place in a rifles chamber when firing.

Ron

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There have been adapters for small ring barrels with large receivers.

 

I remember a long thread about the matter too :)

 

If I needed to do what you're talking about, I'd do just that.

 

I'd be sure and match the inside threads with the outside threads so the bushing is at its maximum wall thickness.

 

I'll put in a comment though... for the amount of time and work you're doing, getting one of those "new" 19 inch military "pulls" in 7x57 would sure be easier.

 

These are listed at $40:

 

http://www.e-gunparts.com/DisplayAd.asp?ch...perSKU=&MC=

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Thanks. The 40.00 barrel ain't bad-wish it was a little longer. I need more than a thread diameter adapter, though. The 7 mag chamber is deep and huge so a bunch of barrel is going to get cut off. I will need to replace the bulk area of the chamber once it's cut cause the win barrel tapers down right away. This is hard to explain - I don't think I'm coming across. I need to make a sketch and attach it.

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I understand exactly what you're talking about.

 

I think even with fine threads, that OD barrel diameter at the shank will be very thin. I equate this as a situation on par (or perhaps worse) than the magnum-in-the-Turk scenario. Perhaps a 7x30 Waters or a 7MM TCU (based-on the .223 case).

 

My gut feeling is that the .470" case base diameter is too great for what you are doing. If you want a 7x57 on the cheap, get a 19.5" barrel.

 

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Thanks for the ideas. Something was telling me the cross sections were going to end up too thin. The thicker the barrel wall the thinner the sleeve and vice versa. It was as much to use up a 7 mag barrel as save money. I wish Adams and Bennett sold their barrels unthreaded also. I don't like fitting a 60 deg thd into a 55.

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