Rechambering a .260 Remington to 6.5 x 47 Lapua - Can it be done?

[arizonajake]

I have 3 silhouette rifles chambered in .260 Remington, all with fairly "new" barrels and I am interested in converting one to 6.5 x 47 mm Lapua by asking my gunsmith to cut 3/8" from the rear of the barrel, re-thread and run the 6.5 x 47 reamer through what is left of the old .260 chamber. Is this enough to clean up?

As usual, any assistance is greatly appreciated in advance.

JB

 

[Jay Christopherson]

JB, the numbers I see show a shoulder diameter of .4578" for the 6.5x47 and .4551" for a .260 Remington (match chamber) and a base to shoulder length of 1.400" vs. 1.5542" respectively.

Your plan to remove .375" and chamber to 6.5x47 *should* work, assuming your numbers are close to these. By the time you remove that amount, the 6.5x47 reamer should be cutting clean dimensions everywhere. In my opinion. If it were me, and barrel length wasn't an overriding concern, I would cut the tenon off entirely (or nearly so) and cut a clean chamber though.

EDIT: All of this assumes the same action.

 

[XTR]

My first question would be why would you want one of your three rifles chambered in a different caliber that is the ballistic twin of a 260Rem? To me that just looks like more reloading headaches.

Second, you may not be able to do what you are trying to do. I'm no gunsmith, but I've spent a lot of time with mine fiddling with my rifles. There is a relief cut at the front of the threaded section of your barrel stub, your choices are probably to take off two or three threads. I think I remember it being .060 per thread or to cut off the stub and start over. Taking off 3/8 of an inch may leave you with not enough threaded barrel stub. At least I think that's what you are going to find out.

 

[Jay Christopherson]

There is a relief cut at the front of the threaded section of your barrel stub, your choices are probably to take off two or three threads. I think I remember it being .060 per thread or to cut off the stub and start over. Taking off 3/8 of an inch may leave you with not enough threaded barrel stub. At least I think that's what you are going to find out.

A chicken groove is optional, not required... It depends on who did the initial work and whether they threaded to the shoulder without a relief cut. I've done exactly what he's asking about (although I re-threaded/chambered in the same caliber, rather than switching) and depending on the work his original smith did, it can be done.

 

[Erik Cortina]

Jay is correct. Most high end smiths do not do a "chicken groove", thus it would be easy to just cut off the required amount and rechamber.

I myself do not do a "chicken groove" and have set a barrel back on my Panda .111" (there's a reason for that number). You can't tell that it was set back because I simply chased the original threads.

 

[arizonajake]

Thank you all for the responses. I was going to convert to 6.5 x 47 due to the magazine in my Rem 700 not being long enough to accept .260 rounds loaded with Sierra 142 MKs. I'll order a new barrel for 6.5 x 47 and install it on my Sako AII to make a new Hunter Class silhouette rifle.
JB

 

[claymore]

Eric, let me guess ? 18 tpi. 2 threads removed. .055555 per thread. That might be the reason. P=1/n. Call me sometime.

 

[Erik Cortina]

Erik, let me guess ? 18 tpi. 2 threads removed. .055555 per thread. That might be the reason. P=1/n. Call me sometime.

You are correct Ronnie.
You taught me well.

 

[AckleymanII]

Jake, there is one more consideration. Be sure that the gunsmith that you choose has a set of pilots that goes with each caliber. The Pilots are graduated in 0.0002 increments. They must fit the correct pilot to the bore. If a pilot too small is used, then the reamer will not be held in line with he bore resulting in a screw ball chamber.

 

[Erik Cortina]

Jake, there is one more consideration. Be sure that the gunsmith that you choose has a set of pilots that goes with each caliber. The Pilots are graduated in 0.0002 increments. They must fit the correct pilot to the bore. If a pilot too small is used, then the reamer will not be held in line with he bore resulting in a screw ball chamber.

^ Myth.


Just take it to a qualified gunsmith and tell him what you want to do and drop it off. Don't tell him how to do it or ask questions that "you read on the Internet" as that will put you at the top of his "s**t list" real quick.

 

[XTR]

I was going to convert to 6.5 x 47 due to the magazine in my Rem 700 not being long enough to accept .260 rounds loaded with Sierra 142 MKs.

I did not realize that the 6.5x47 was sufficiently different in case dimension to allow seating the longer bullets out further in a mag length OAL. If that is truly the "case" then I'll have to look hard into that. I've got a stock here that I've been planning to put a 260 into for a couple of yrs now and just never gotten to it. If the 6.5x47 really buys some significant OAL gain then it may end up a 6.5x47 and not a 260Rem.

 

[jcampbellsmith]

I was going to convert to 6.5 x 47 due to the magazine in my Rem 700 not being long enough to accept .260 rounds loaded with Sierra 142 MKs.

I did not realize that the 6.5x47 was sufficiently different in case dimension to allow seating the longer bullets out further in a mag length OAL. If that is truly the "case" then I'll have to look hard into that. I've got a stock here that I've been planning to put a 260 into for a couple of yrs now and just never gotten to it. If the 6.5x47 really buys some significant OAL gain then it may end up a 6.5x47 and not a 260Rem.

I've had a Wyatt's Extended Magazine Box fitted to a couple of my rifles to allow me to go up to 3.1 inches in OAL. In practice the rounds are loaded to just under 2.9 inches giving me a 0.2 inch gap in front of the bullet tip.

http://www.thestalkingdirectory.co.uk/gallery/member-galleries/p2948-remington-700-sa-in-260-rem.html

I've also got a magazine fed 260 Rem, but I probably will only shoot 123gr/129gr bullets out of that.

Regards

JCS

 

[XTR]

I was going to convert to 6.5 x 47 due to the magazine in my Rem 700 not being long enough to accept .260 rounds loaded with Sierra 142 MKs.

I did not realize that the 6.5x47 was sufficiently different in case dimension to allow seating the longer bullets out further in a mag length OAL. If that is truly the "case" then I'll have to look hard into that. I've got a stock here that I've been planning to put a 260 into for a couple of yrs now and just never gotten to it. If the 6.5x47 really buys some significant OAL gain then it may end up a 6.5x47 and not a 260Rem.

I've had a Wyatt's Extended Magazine Box fitted to a couple of my rifles to allow me to go up to 3.1 inches in OAL. In practice the rounds are loaded to just under 2.9 inches giving me a 0.2 inch gap in front of the bullet tip.

http://www.thestalkingdirectory.co.uk/gallery/member-galleries/p2948-remington-700-sa-in-260-rem.html

I've also got a magazine fed 260 Rem, but I probably will only shoot 123gr/129gr bullets out of that.

Regards

JCS

WOW! I didn't know Wyatt's made that one. Sweetness, that mag could hold my F-TR loads with no problems (well, most of them). It would easily handle up to a 200gr bullet and not intrude on the case.

Just did a quick look, the extended box is for internal mags. Has anyone done anything like this for detachable mags?

 

[Keith McIntyre]

I intend to experiment with my Sako L579 that has been fitted with a CDI bottom metal that accepts AICS & Magpul mags. I don't have the mags at hand, but if I remember correctly they both have a filler strip at the rear of the mag. If so, it may be as "easy" as removing that strip as long as you can change your bolt stop to allow the bolt to get behind the round. On Sakos that mod isn't as easy on some others. I think that I'm going to be required to relocate the entire bolt release/stop !0.25" to the rear. This will require the servives of a machinist to open the slot and D&T a new hole(s). Luckily I know a very good precision machinist, not cheap but very skilled. Wish me luck! first order of business is to verify that the mags can be modified. A filler may be required at the rear of the existing mag follower. The things that we put ourselves through!!