The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > The Smithy

Thread Tools Search this Thread
Old November 5, 2008, 05:36 PM   #1
Junior Member
Join Date: February 1, 2008
Posts: 12
dumb question

If I want to convert a ruger m77 mII that is in .257 roberts to a 7x57 what do i need to do?

Is it just a matter of finding a decent gun smith and having the barrel changed to fit the larger caliber?
243Ben is offline  
Old November 5, 2008, 05:52 PM   #2
Jim Watson
Senior Member
Join Date: October 25, 2001
Location: Alabama
Posts: 14,162

The .257 Roberts is so close to a .25x57 that there should be no other work required besides replacing the barrel.

I don't know the current availablility, .257s seem to come and go and if Ruger is not making any right now, you might could make an advantageous trade. If they are making 7x57s. Alternatively the takeoff .257 barrel should sell pretty readily.
Jim Watson is online now  
Old November 5, 2008, 08:16 PM   #3
Senior Member
Join Date: September 19, 2008
Posts: 4,678
A second alternative is that the .257 barrel can be simply rebored/rifled to .284 w/o any other changes, either (except a new muzzle crown).

Of course, it'll carry the old cartridge designation, unless remarked.

PetahW is offline  
Old November 5, 2008, 09:00 PM   #4
James K
Join Date: March 17, 1999
Posts: 24,160
I haven't checked prices lately, but it may well cost more to rebore and re-rifle than to just have a new barrel installed. Plus there are a limited number of shops that do that kind of barrel work and they are always months behind.

One possibility would be to try one of the major barrel makers and see if they would convert your barrel; I have been told some do that but I have not had it done.

Jim K
James K is offline  
Old November 6, 2008, 08:27 PM   #5
T. O'Heir
Senior Member
Join Date: February 13, 2002
Location: Canada
Posts: 8,369
"...may well cost more to rebore and re-rifle..." Definitely would. Machine shops are charging $100 plus per hour and you'd need a smithy with the right equipment.
Rebarreling is the way to go. However, the 7mm Mauser OAL is 296 thou longer than the Roberts so you'll likely have a mag length issue.
Spelling and grammar count!
T. O'Heir is offline  
Old November 7, 2008, 02:37 AM   #6
Senior Member
Join Date: February 13, 2006
Location: Washington state
Posts: 12,865
However, the 7mm Mauser OAL is 296 thou longer than the Roberts so you'll likely have a mag length issue.
The 257 Roberts is a 7X57mm case necked to 25 caliber. Same length. The 257 Roberts is already chambered in a long action, same as the 7X57mm, so there are no magazine problems. The only issue will be replacing the barrel. Douglas, ER Shaw, or McGowen will do rebarreling. Of the 3, only ER Shaw does rebluing, AFAIK. Or you can buy any barrel you want and have a local guy do it all.
Never try to educate someone who resists knowledge at all costs.
But what do I know?
Summit Arms Services
Taylor Machine
Scorch is online now  

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 07:58 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2017 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent:
Contact Us
Page generated in 0.11587 seconds with 7 queries