In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
Rechambering
Alan Rushing
Member Posts: 8,805 ✭✭✭
Regarding potentially rechambering of take-off barrels.
1)Would rechambering a take-off barrel from .300 Win Mag to .300 RUM be doable and reasonable (financially)?
2)Would it be cost effective, if one is rebarreling? Is it better to get the correct chambered barrel to start with? Or is it best to just order the appropriate new barrel from the get go?
I have not as yet rebarreled any of my rifles, but need to do so. (Have not located gunsmith near by ... have to tie in with someone outside of my immediate area, so have been unable to converse directly with experienced gunsmith as yet.)
- - - - - - - - -
Hello Bruce,
Figured that might be the way that it would break. The rifle I have in mind is a hunting rig.
I know that it would depend on region, the Smith and such, but any idea of what is charged for rechambering and switching out the barrels?
Appreciated.
1)Would rechambering a take-off barrel from .300 Win Mag to .300 RUM be doable and reasonable (financially)?
2)Would it be cost effective, if one is rebarreling? Is it better to get the correct chambered barrel to start with? Or is it best to just order the appropriate new barrel from the get go?
I have not as yet rebarreled any of my rifles, but need to do so. (Have not located gunsmith near by ... have to tie in with someone outside of my immediate area, so have been unable to converse directly with experienced gunsmith as yet.)
- - - - - - - - -
Hello Bruce,
Figured that might be the way that it would break. The rifle I have in mind is a hunting rig.
I know that it would depend on region, the Smith and such, but any idea of what is charged for rechambering and switching out the barrels?
Appreciated.
Comments
Strictly for hunting a factory barrel will suffice, if it's for any competition a custom is called for or your winning chances are not so good as a rule.......
The 300RUM OAL is over 1/4" longer and fatter at the neck and base.
The bolt face will work though.
"1)Would rechambering a take-off barrel from .300 Win Mag to .300 RUM be doable and reasonable (financially)?"
It is both doable and can be reasonable depending on your sensitivity.
- Take off barrels are usually factory and as such cost about $12.00 to make.
- Factory barrels not only require the chamber work but you have to time the barrel also so the roll mark information comes up top dead center or left/right.
The RUM does clean up the existing chamber. But it isn't as simple as jamming the reamer in and cutting the chamber.
When the original chamber is cut, the pilot on the end of the reamer fits the bore diameter almost exactly, usually within 0.0001" or 0.0002" whether a solid pilot or a bushing pilot. This fit is critical to the accuracy and concentricity of the chamber.
When you try to ream inside an existing chamber the pilot has nothing to contact because of the diameter of the chamber, until near the very end of the cut. This lack of support allows the reamer to chatter and move away from the center line of the bore. In essence, the quality of the new chamber can suffer unless other methods are employed. Sometimes you get lucky and the gun gods smile on your endeavor, other times, the bear bites you.
It's a crap shoot.
There is a thriving market for take-off barrels and re-chambering. But it's up to the individual and their sensitivity to quality and accuracy or economy which guides the decisions.
I prefer to use a good barrel blank and cut an original chamber. Then there aren't any questions nagging at the back of your mind about quality and accuracy.
Best.
A helical reamer would be better than a straight fluted one.
Maybe Clymer or others can make a long piloted rougher reamer.
Again, have you considered action length, magazine and feed rail changes for this longer,fatter cartridge?
Best
The above comments were intended as a "pick-up" on v35's question about possible magazine, and maybe more importantly, feed ramp considerations.
Specifically, as already mentioned, a non-issue with something like the Ruger #1, Maybe or maybe not a question with the other bolt guns.
Let's cut to the chase here.
Action length:
Of the ones mentioned; "Ruger No. 1, 700, 77, 70, 98 or?", the only one that would give a gunsmith pause is the Ruger M77. A Ruger #1 will feed anything up to and including a .416 Rigby, M700's serve the RUM up every day, M70's have been available in the .375 H&H which is the same OAL as the RUM and the M98's have been chambered in everything up to the venerable .505 Gibbs. So really, what difference does the action brand have to do with this discussion?
And if you really wanted to be a stickler for accuracy, all you need to do is fit a detachable box magazine and away you go!
"A good lathe hand could bore the .300 Win Mag chamber close enough to finished size for the RUM pilot to get a purchase on the bore."
As a matter of fact, I am a good 'lathe hand', both manual and CNC. It doesn't matter how good you are, boring out the existing chamber until you get contact with the pilot will result in getting the chamber done by boring period.
"A helical reamer would be better than a straight fluted one."
If this were the case, I'd have $10,000.00 worth of helical chamber reamers. Since it's not true, I don't. We've tried every combination of shape, angles, relief, etc. and the standard straight flute reamers work the best with new and re-cut chambers.
"Maybe Clymer or others can make a long piloted rougher reamer."
Like this is going to be an affordable solution? A custom, one-of-a-kind reamer to cut one chamber? Somehow I don't think so.
I think if you want a beater truck gun with ho-hum potential accuracy, go with the re-chamber.
However, the reality of the situation is that you will be better served by a new barrel from a top named barrel maker and having a quality gunsmith do the rest.
I'm sure there will be a long line of wannabe exceptions but the general concept will be true today, tomorrow and into the foreseeable future.
Best regards and good luck with your project!
ADDED:
Fit and feed is a non-issue as well since this is a part of gunsmithing on rifles and will usually be required to a lesser or greater extent every time you choose to re-chamber. This is true unless the new chamber can use the same geometry as the original.
Best.
Make sure the prices quoted include magazine work on both action and stock.
In my experience, there's a wide difference in machine shop skills so
you may get some reasonable rechambering quotes.