can you rechamber a 308 barrel into 300WinMag?

[Whitebeard]

The actual machine work involved in re-chambering a barrel is substantially less then that of fitting and machining a new barrel blank.
A smith may tell you that the machine work costs as much as fitting a new barrel to disuade you from having the work done because he knows he will not make much money on the job.
If he does take the job on and charges you any where near the price for fitting a new barrel then you are being ripped off.

Ian.

 

[see it shoot it]

The actual machine work involved in re-chambering a barrel is substantially less then that of fitting and machining a new barrel blank.
A smith may tell you that the machine work costs as much as fitting a new barrel to disuade you from having the work done because he knows he will not make much money on the job.
If he does take the job on and charges you any where near the price for fitting a new barrel then you are being ripped off.

Ian.

why would it be less work,surely the opposite as if the existing chamber isnt true to the bore what do you clock off to get it all straight and true ?? aslo wouldnt the throat area be harder due to heat being generated through firing
if you break the cost of a new barrel job down which is about £700 on average,barrel cost around £350 thats leaves £350 for labour and proofing costs

 

[Whitebeard]

why would it be less work,surely the opposite as if the existing chamber isnt true to the bore what do you clock off to get it all straight and true ?? aslo wouldnt the throat area be harder due to heat being generated through firing
if you break the cost of a new barrel job down which is about £700 on average,barrel cost around £350 thats leaves £350 for labour and proofing costs

We are talking about rechambering which does not involve the turning and threading of the tennon , if you mean setting back and rechambering then there would be a little more machine work.
If there is enough barrel shank to allow removal of the tennon, re-turning and re-threading, then the machine work would be the same, however you still dont need to factor in the cost of a new barrel blank

 

[see it shoot it]

We are talking about rechambering which does not involve the turning and threading of the tennon , if you mean setting back and rechambering then there would be a little more machine work.
If there is enough barrel shank to allow removal of the tennon, re-turning and re-threading, then the machine work would be the same, however you still dont need to factor in the cost of a new barrel blank

to change a 30.06 to a 300 win mag you will have to cut and re thread the tennon hence it would cost the same amount of labour as fitting a new barrel which is about £350 inc proof

 

[enfieldspares]

Why? I am under the impression that an awful lot of post WW2 303 calibre Bren guns were rechambered into 7.62.........

No they weren't! The chamber is in the detachable barrel. So it is pretty much a change of barrel and a modification to a different extractor and, save modification to take the new 7.62mm magazine the job was done. Apart from re-calibrating the sights. So they were in essence fitted with new 7.62mm barrels and some of the working parts modified or replaced.

ANYWAY...308 to 300 W M.:

The favoured conversion form 30-06 was originally to 308 Norma Magnum. In fact the 308 N.M. was DESIGNED so that rifles in 30-06 could be re-chambered to that caliber.

In its essence provided you are careful and now what you are about it is just a matter of inserting a chamber reamer and with a 308 you aren't even changing the "calibre" noted on your FAC as it stays as a 308!

So all this talk about it costing XXX hundreds of pounds is so much "puff"! It is as simple as buying a chamber reamer and doing it BY HAND if you are careful.

In fact it was designed to be done without removing the barrel from the action. So I really don't know where all these fanciful cost figures come in.

The 300 Winchester Magnum arrives after the (better) 308 Norma Magnum and was designed so that 308 Norma Magnum rifles could be easily re-chambered to 300 Winchester Magnum.

Thus the reason that the Winchester product has that ridiculous short neck...not a lot of people know that...and case body that is longer than the case body of the Norma cartridge.

And it goes on...the 300 Weatherby Magnum being designed so that 300 Winchester Magnum rifles could also be re-chambered.

Me? I'd take a strong look at the 308 Norma Magnum option.

FWIW I think that the 308 Norma Magnum has advantages too in that the shoulder does not go so far up the barrel shank as does the Winchester product.

 

[Simjim33]

why would it be less work,surely the opposite as if the existing chamber isnt true to the bore what do you clock off to get it all straight and true ?? aslo wouldnt the throat area be harder due to heat being generated through firing
if you break the cost of a new barrel job down which is about £700 on average,barrel cost around £350 thats leaves £350 for labour and proofing costs

Thats quite a statement!!!
An even bigger statement!!!!!

to change a 30.06 to a 300 win mag you will have to cut and re thread the tennon hence it would cost the same amount of labour as fitting a new barrel which is about £350 inc proof

????????????????

I am actually thinking it would just be the last part.
I have an option on a 30-06 which has barely been shot, get it sent to machinist and hey presto it comes out WinMag as per variation!

That answers that imaginary hardening problem Edd!!

Ahh I see.in that case you either bite the bullet so to speak and have a donor re barreled or just buy a win mag

Edd makes good use of what he has and is very innovative. Skills we should all develop I think.
Why get a new barrel if it is in good condition and the right calibre? or are you touting for business?

 

[bewsher500]

No they weren't! The chamber is in the detachable barrel. So it is pretty much a change of barrel and a modification to a different extractor and, save modification to take the new 7.62mm magazine the job was done. Apart from re-calibrating the sights. So they were in essence fitted with new 7.62mm barrels and some of the working parts modified or replaced.

Ha, rumbled!
I know next to nothing about Bren guns apart from the awesome noise!
stole that snippit from this:
British early post WWII rifles and mgs

to change a 30.06 to a 300 win mag you will have to cut and re thread the tennon hence it would cost the same amount of labour as fitting a new barrel which is about £350 inc proof

I may be missing something here as I am no gunsmith but I cant see it
Why would you cut the tenon off?

the barrel is going back on the same action so thread remains the same,
the case length is barely 2mm longer (30-06-300wm) and 0.75mm wider at its widest point.
the only defining feature is the belt which is easy to cut in
its a rebore at best with no other features changing

if the donor chamber is off centre it wouldnt be used neither would the barrel be used if rifling was worn away, throat was erroded/crack or the action was as sloppy as a Leeds dinner lady.


the more I think about the more I am talking myself into it!
have sent three emails to some well know gunsmiths, will report back

 

[see it shoot it]

Thats quite a statement!!!
An even bigger statement!!!!!



????????????????



That answers that imaginary hardening problem Edd!!



Edd makes good use of what he has and is very innovative. Skills we should all develop I think.
Why get a new barrel if it is in good condition and the right calibre? or are you touting for business?

touting for nothing as i aint no barrel plumber,mind you I do know a couple.neither would take on such a job as silk purse and sows ear springs to mind LOL
by the way there not big or bigger statements,thats what will have to happen to get the job done correctly

 

[Simjim33]

why would it be less work,surely the opposite as if the existing chamber isnt true to the bore what do you clock off to get it all straight and true ?? aslo wouldnt the throat area be harder due to heat being generated through firing
if you break the cost of a new barrel job down which is about £700 on average,barrel cost around £350 thats leaves £350 for labour and proofing costs

to change a 30.06 to a 300 win mag you will have to cut and re thread the tennon hence it would cost the same amount of labour as fitting a new barrel which is about £350 inc proof

I am actually thinking it would just be the last part.
I have an option on a 30-06 which has barely been shot, get it sent to machinist and hey presto it comes out WinMag as per variation!

Ahh I see.in that case you either bite the bullet so to speak and have a donor re barreled or just buy a win mag

touting for nothing as i aint no barrel plumber,mind you I do know a couple.neither would take on such a job as silk purse and sows ear springs to mind LOL
by the way there not big or bigger statements,thats what will have to happen to get the job done correctly

But you haven't even seen the rifle how do YOU know the chamber/barrel is not true? Unless, it is your rifle, your trying to pass off!
plus,
you "aint no barrel plumber" so why would you come out with a statement like that!!!!??????

 

[see it shoot it]

But you haven't even seen the rifle how do YOU know the chamber/barrel is not true? Unless, it is your rifle, your trying to pass off!
plus,
you "aint no barrel plumber" so why would you come out with a statement like that!!!!??????

because if you have had anything to do with factory rifles when there taken apart you would understand what Iam mean,and sorry to disapoint you yet again but No its not my rifle.
anyway seems you just spopiling for an argument so i will leave it at that,good luck to the OP hope he dosent waste his hard earned

 

[Whitebeard]

to change a 30.06 to a 300 win mag you will have to cut and re thread the tennon hence it would cost the same amount of labour as fitting a new barrel which is about £350 inc proof

No you dont, the 300 Win Mag is longer then the 30-06 so its a straight forward rechambering job, set the correct headspace, carry out any bolt face modifications, refit the barrel and hey presto you are ready to go

Ian.

 

[Muir]

why would you need to touch the existing tenon?
you are just removing 0.75mm from the wall of the existing chamber diameter and 2mm into the throat for the extra neck length

seems very straightforward to me





interesting.
will this not create issues and potential inaccuracies with resizing?

Not really. IF you just screw down the FL sizer, maybe, but we all resize to fit our individual chambers, correct? It was proven by the US Army Marksmanship Unit's gunsmiths that 300WM headspaced on the shoulder shot circles around guns headspaced on the senseless belt. I've seen the data and I've seen the targets. Very impressive. ~Muir

 

[Brithunter]

In answer to this earlier questions as to why this is:-

Funny thing is that thy didn't seem to have a problem with this or proofing them under CIP. Yet here in the UK it's not possible and MUST have a new barrel.

Tis simple the smiths want to make as much as possible and telling the gullible customer that it MUST be a new barrel is one way to maximise the cost and mark up. Hence the quote for more than supplying and fitting a new barrel for a simple re-chamber.

I also noted the comment that alluded to that all factory barrels are not true yet a custom barrel will be ..................................... that is just so wrong. When I re-chambered that BSA barrel to 280 AI I clocked up the chamber to make sure it was true and then cut the new one. I did have to alter the tenon but only because there was a slight difference in the later teno to the earlier one so it was machined to match the earlier one as it was going onto and earlier action. The breech counter bore also had to be altered for the same reason.

I also objected to the "Smith" telling me that i would have to pay for the reamer as he did not have one in 280 AI but then he would keep the reamer.............................................. yeah right. Should I ever require "Smithing" work on a rifle his establishment is right down the bottom of the list to contact!!!!!!!!!!!!!!!!!!!!!! I will also never recommend him to anyone and this despite my sending work his way before.. He worked on two rifles for me before this but not no more.

 

[Simjim33]

I hope you dont mind this Edd but,

In the spirit of this kind of thing.

I remember reading a book about basic gunsmithing (a few years ago ). it was an old book, but, in there I seam to remember a bit about re-chambering a rifle with out a lathe. I cant remember exactly how it was done as I kind of skimmed through that bit.

But can that be done?

Is there a tool to Center the reamer?
I know there are some FLO's that dont like you doing things your self. So please dont go down that sidetrack. I do know that once you have cleared it with your FLO (in my case hampshire) certain things can be done.
Also the issue of "proofing" would need clarification (I had an interesting talk with my FEO on this subject too. so i know what my FLO position is regarding this)

My question is more aimed at experienced people like Muir,Brit, Joe BLogs and Red mist.

 

[enfieldspares]

I remember reading a book about basic gunsmithing (a few years ago ). it was an old book, but, in there I seam to remember a bit about re-chambering a rifle with out a lathe. I cant remember exactly how it was done as I kind of skimmed through that bit.

I'll answer YOUR question with a question.

Can you tap a piece of steel, with a pre-drilled hole in it, for a bolt without a lathe?

Say where you are going from a 6mm bolt to an 8mm bolt?

Of course you can. You do it by hand. In fact most precision 22 Rimfire rilfes used to be so done.

And for the average man without a precision lathe in fact it is the best way to go if you do it right and have reamers suitable. And assuming that you have a piece of full length rifled but un-chambered barrel.

If you go on the American forums you will get a lot of people that have done just that.

So you could go from an existing barrel already chambered in 308 to 30-06 to 308 Norma Magnum doing it by hand. And probably just about "get away" with just using finishing reamers. As a "one off".

As far as Proof is concerned that is always a wise thing to do, just to cover yourself, AND if you have any intent on using the thing where a third party may be involved. But essentially Proof is concerned about protecting "the paying public" so no, if it is for you and you alone then it does not legally have to be proved. But if it is to be transferred from you to another (either an individual OR an RFD) by sale either directly or indirectly or by auction then it must be "in Proof".

There's a lot of hogwash talked here about doing things that just because it is a firearm seem shrouded in "mystery" yet if you did the exact same thing, to the exact same precision on something that was not a firearm, it would be no "mystery" but "simples"!

I've had guns repaired by good, expert, precision welders who as long as you explain what is needed and why; and what can get hot and what can't get hot grasp the concept very quickly. Guys that wouldn't know one end of a gun from another but are expert in welding and metallurgy.

 

[j0e_bl0ggs]

But can that be done?
Is there a tool to Centre the reamer?

The reamer generally has a fixed or removable 'pilot' to guide the cutter.

Of course you can. You do it by hand. In fact most precision 22 Rimfire rilfes used to be so done.
And for the average man without a precision lathe in fact it is the best way to go if you do it right and have reamers suitable. And assuming that you have a piece of full length rifled but un-chambered barrel.

There is your answer!

There's a lot of hogwash talked here about doing things that just because it is a firearm seem shrouded in "mystery" yet if you did the exact same thing, to the exact same precision on something that was not a firearm, it would be no "mystery" but "simples"!

Absofrikkinglutely!!!

 

[Brithunter]

I cannot recall where the article was but I do recall the photograph of the the gunsmith chambering the barrel by hand. The barrel was held vertically in a bench vice and it was a "Medium" bore calibre intended for Plains game. The photo was taken in Rigby's of London works.

 

[news of the world]

re-chamber to 30/284,no bolt problems and can be still in a short action.

 

[bewsher500]

re-chamber to 30/284,no bolt problems and can be still in a short action.

interesting
308 with a bigger case?

 

[Whitebeard]

interesting
308 with a bigger case?

Or even .300 WSM, it has a nice short fat case which will work in a short action, is ballistically similar to the 300 Win mag and has a slightly rebated rim to fit the standard magnum bolt face.
Being a beltless case it headspaces off the shoulder enhancing its accuracy potential

Ian.