The Firing Line Forums

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

Reply
 
Thread Tools
Old January 11, 2010, 02:26 AM   #1
herroprease
Member
 
Join Date: January 11, 2010
Posts: 36
how to bore a rifle

i have a 300 win mag and i want to bore it out to a 338 win mag. the cartridge seems very similar in length.does anyone have any tips or info on what i have to do?
herroprease is offline  
Old January 11, 2010, 02:33 AM   #2
Swampghost
Senior Member
 
Join Date: April 18, 2008
Location: Florida, east coast
Posts: 2,106
Gunsmith or machineist that really likes guns. You could always just buy a new barrel.
__________________
NRA Patron Member
Swampghost is offline  
Old January 11, 2010, 04:26 AM   #3
Bud Helms
Staff
 
Join Date: December 31, 1999
Location: Middle Georgia
Posts: 12,995
That would be a rechambering and reboring. I don't believe you will get away with a rebore and not a rechamber.

That's why they make replacement barrels.
__________________
"The irony of the Information Age is that it has given new respectability to uninformed opinion." - John Lawton, speaking to the American Association of Broadcast Journalists in 1995
Bud Helms is offline  
Old January 11, 2010, 08:55 AM   #4
mapsjanhere
Senior Member
 
Join Date: August 6, 2009
Location: Albuquerque
Posts: 2,344
CNC Lathe - $14,000
Drill, groove cutter, reamer, gauges - $500
Having made your own .338 blunderbuss - priceless

I'd go with Bud's advise, a rebarrel with correct head space can be had for around $350.
__________________
F 135 - the right choice
mapsjanhere is offline  
Old January 11, 2010, 09:21 AM   #5
PetahW
Senior Member
 
Join Date: September 19, 2008
Posts: 4,679
You need to be set up like a rebore shop, with the beans to rebore the barrel larger (deep hole drilling), and a rifling machine/fixture.

The base cartridges are the same, so a simple rebore/rerifle should dothe trick - although I haven't checked the cartridge specs against each other to see whether or not the barrel needs a rechambering, or a setback, or nothing else due to cartridge/shoulder length.

Unless your already setup & good to go, the $245 a rebore shop like Jes Ompaugh (sp?) in OR charges is a waaaay easier, less costly, way to go.

.
PetahW is offline  
Old January 11, 2010, 09:54 AM   #6
LongRifles, Inc.
Senior Member
 
Join Date: October 21, 2009
Location: Black Hills of S. Dakota
Posts: 195
First, it's quite, quite rare for someone to do this when a premium match grade barrel can be bought and installed for around $600 bucks.

Also, It's not as simple as a CNC lathe. I own two slantbed turning centers and I wouldn't be able to do this on either of my machines. A deep hole gun drill probably a more appropriate machine. In this case you'd skip the drilling portion and ream the bore to the larger caliber. Then either recut the rifling, rebutton, or broach it.

Either way it's a task that 90% of gunsmiths out there would avoid as it's just much simpler and less brain damage for everyone to just hang a new stake on the receiver.

Hope this helped.

C
__________________
LongRifles, Inc.
"More than a business,
This is a lifestyle."

www.longriflesinc.com
LongRifles, Inc. is offline  
Old January 11, 2010, 01:36 PM   #7
brickeyee
Senior Member
 
Join Date: December 29, 2004
Posts: 3,342
Rifling is harder than just boring to size.

A new barrel would probably be cheaper.
brickeyee is offline  
Old January 11, 2010, 02:00 PM   #8
5whiskey
Senior Member
 
Join Date: October 23, 2005
Location: US
Posts: 1,544
Definately re-barrel. I wouldn't have even thought of re-boring. I've used barrels from ER Shaw several times, and I've had sub moa accuracy from all of them. ER Shaw will ship a barrel in the white to your door for around 200 bucks. I can headspace, attach, and parkerize myself, so I can get out cheap. You could probably find a smith to blue or park and mount the barrel for around 250. Don't get stiffed on the blue job. There won't be a tremendous amount of prep work going into a shaw barrel if bluing. With park, normal prep and blasting will be in order.
5whiskey is offline  
Old January 11, 2010, 02:37 PM   #9
Jim Watson
Senior Member
 
Join Date: October 25, 2001
Location: Alabama
Posts: 10,920
The REAL problem, even for a pro gunsmith, is that it cannot be done except by setting the barrel back, rethreading and rechambering after the rebore. The .300 W.M. is .156" LONGER from head to shoulder than the .338 W.M.
Jim Watson is offline  
Old January 15, 2010, 02:39 PM   #10
James K
Staff
 
Join Date: March 17, 1999
Posts: 19,169
"How to bore a rifle."

My first thought was, "Sit it down and tell it stories about your hunting trips."

Jim
__________________
Jim K
James K is offline  
Old January 15, 2010, 03:41 PM   #11
jaguarxk120
Senior Member
 
Join Date: February 28, 2008
Location: Michigan
Posts: 1,928
Go to www.cutrifle.com the do reboring/rifling.
jaguarxk120 is offline  
Old January 19, 2010, 09:40 AM   #12
apr1775
Senior Member
 
Join Date: May 3, 2007
Location: Virginia
Posts: 420
The only case I'd go for reboring is if the existing bore is totally shot out and there is something of value on the outside of the barrel, such as special sights or you need to preserve the exterior look of a classic rifle. In most cases, it would be more cost effective to re-barrel. If your bore is good, I'd stick with 300wm as it should handle anything that the 338 can handle, especially if you reload.
__________________
Don't focus so much on who is driving the bus, but pay attention to what bus you're on and where it's going.
apr1775 is offline  
Old January 25, 2010, 07:17 PM   #13
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 4,443
Note that reboring and rerifling a barrel will usually end up with one that's not too accurate. The reason is the first inch or so of the new bore and groove dimensions at each end are not the same as the dimensions between these two points. New barrel blanks have their muzzle's cut off an inch or so and the chambering reamer takes out the bad part at the back end. Some custom after market barrels were marked with a line at each end denoting that the dimensions between these front and back marks were the best part of the barrel.

If one wants to preserve a barrel's outside finish, marks and dimensions, it's best to have it gun drilled to an oversize dimension then have a liner made to fit it. Assuming one can make a liner a "shrink fit" by having it a few ten thousandths larger than the gun drilled barrel, then freezing the liner and heating the barrel, the liner could be pressed in. The result may be as strong and save as the original barrel. But this will cost a very thick billfolds dollar supply.
Bart B. is online now  
Old January 25, 2010, 09:58 PM   #14
bigautomatic
Senior Member
 
Join Date: December 18, 2005
Location: Ohio
Posts: 610
Bart- Are there smiths out there that would line a centerfire barrel? I'm probably just way out of the loop on this topic, but I was under the impression that only rimfires could be safely lined. Enlighten me if you could.
bigautomatic is offline  
Old January 25, 2010, 10:27 PM   #15
guns and more
Senior Member
 
Join Date: January 16, 2009
Location: Florida
Posts: 101
Quote:
how to bore a rifle
Make it watch Barbara Streisand movies.
guns and more is offline  
Old January 26, 2010, 07:05 AM   #16
mega twin
Senior Member
 
Join Date: August 15, 2006
Posts: 424
guns and more,I think they outlawed that at Gitmo
mega twin is offline  
Old January 26, 2010, 11:37 PM   #17
James K
Staff
 
Join Date: March 17, 1999
Posts: 19,169
You can't line a barrel for a high pressure cartridge using the normal liners, they are too thin. The problem is that no liner can be made to fit perfectly with full support at all points, so the liner has to be thick enough to stand the pressure by itself. The usual liners (as sold by Brownells and others) are made for .22 and older low pressure black powder cartridges like .44-40.

I think Bart is talking about the situation where high pressure is involved, but it is important to retain the original markings, as in a collectors item. As he says, you would have to have a liner specially made (by turning down a standard barrel blank) with sufficient thickness to contain the pressure, and ream out the original barrel to a thin shell. That requires a fair amount of skill, well beyond the usual simple lining job.

Jim
__________________
Jim K
James K is offline  
Old February 4, 2010, 04:09 PM   #18
Idahogunsmith
Junior Member
 
Join Date: January 27, 2010
Location: Boise Idaho
Posts: 9
Geez, I still laughing mao

How to bore a rifle, tell its stories.. God that is classic!
Idahogunsmith is offline  
Reply

Thread Tools

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 06:15 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.10616 seconds with 9 queries