6mm BR norma

sdeering

sdeering

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Hi all. Looking for a little imfo on doing a barrel swap on a surplus 22-250 rem 700 I have late 70s early 80s.
I have found a new take off 243 barrel (BDL).

I would like to rechamber to 6MMBR to fit my action.
Is this possible? Is there enough material to do the rechamber?

That being said, I am looking for a reamer, it can be a neck turn. I am also looking for reamer specks. I am thinking about building one. I have the 6BR specks though I am unsure how much biger the od of the reamer has to be, D2 tool steel OK. Any insight?

I have all the equipment to pull this off. It will be a first time job. I am doing this as a test before I try a aftermarket barrel. If I screw the take off barrel It will be a learning experience.

All advice will be appreciated.

Stephen
 
The 6mm BR is all about fantastic accuracy with a minimum of work.

Have Dave Kiff at Pacific Tool & Die make you a reamer a 6mm BR no - turn neck for Lapua brass and you will not regret it. Tell him what bullet you plan on using... get the throat made to cut as short as you can for that bullet.

Your "test" using a factory 243 barrel and your first attempt is not a good test for the cartridge... the cartridge abilities are proven. You need a good barrel and action and proper Benchrest Gunsmithing techniques to get the most of it. You will never know if the factory barrel is not good or if your technique was faulty if it does not shoot well....

But it is a great cartridge... using Lapua brass is the only way to go as far as I am concerned and the chamber needs to be cut for Lapua or it will not fit usually. It is slightly larger at the rear by a thou or two. There is no advantage to turning necks if you use Lapua brass.

Have fun with it...
 
Thanks Guntech.
What I have read the 6mmbr is a great round.
The 220-250 Rem 700 action donor hasn't been shot in years, although like new. I am going to use it to practice on.

As "test" I mean I am testing my ability at doing a little home smithing.

I have a lathe, cnc mill, regular mill, shaper, heat treating forge, and a whack o other goodies collecting dust, I need to blow the dust off and make something. Three young kids can take up most of ones spare time, things are slowly getting better.

Being a gun nut, I would like to use my machining equipment to make something that goes bang, that’s my goal. I have as much fun tinkering and reloading as shooting for some reason.
If things work out I may order a target barrel in the future to play with. If it shoots like crap I will have no one to blame but me.
The barrel is on the way I will have to check the twist before I can decide on the max bullet I will shoot. The seller said 9 1/8. I have been told on another forum 105 will be max.

I would like to build the reamer as well but it seems specks are non existent for such. Anyone know if there is a rule of thumb for case clearance to chamber? I would guess 3-5 thou.
I would be interested in hearing all advice.
Thanks
Stephen
 
I would add that make sure that your throat is sized for the type of bullets you will use. You bullet choice will be heavily influence by its twist rate...
 
sdeering said:
Thanks Guntech.
What I have read the 6mmbr is a great round.
The 220-250 Rem 700 action donor hasn't been shot in years, although like new. I am going to use it to practice on.

As "test" I mean I am testing my ability at doing a little home smithing.

I have a lathe, cnc mill, regular mill, shaper, heat treating forge, and a whack o other goodies collecting dust, I need to blow the dust off and make something. Three young kids can take up most of ones spare time, things are slowly getting better.

Being a gun nut, I would like to use my machining equipment to make something that goes bang, that’s my goal. I have as much fun tinkering and reloading as shooting for some reason.
If things work out I may order a target barrel in the future to play with. If it shoots like crap I will have no one to blame but me.
The barrel is on the way I will have to check the twist before I can decide on the max bullet I will shoot. The seller said 9 1/8. I have been told on another forum 105 will be max.

I would like to build the reamer as well but it seems specks are non existent for such. Anyone know if there is a rule of thumb for case clearance to chamber? I would guess 3-5 thou.
I would be interested in hearing all advice.
Thanks
Stephen
Click to expand...

Buy the reamer is the best advice I can give. Unless you have the ability to taper grind and cut angles and relief within a 10 thousands of an inch or so... how much to offset the flutes, what steel to use and to heat treat it correctly... You could spend a month pissing around and still end up with a piece of crap to make your chamber with. One good grinding wheel will cost more than a reamer.
 
The only reasons to make a reamer are (a) because you can't wait to get one for a specific job or (b) just to say you can.
If you are a reasonably skilled machinist, you can make a perfectly serviceable reamer. However, unless you are a very skilled toolmaker, it is highly unlike you will be able to come near what you can buy for 100 bucks.
If you are looking for reamer specs (dimensional) you can buy Dave Kiff's book of chamber prints. This is available from Pacific Tool and Gauge. If you want to get right on the rifle barreling, have him send a 6BR reamer along with the book! Regards, Bill.
 
Thanks for the reply Bill
Reasons?
Yes because I can well try.
For machining practice. I don’t do this for a living just hobby. Its nice to get out of the house for a bit too.

It looks like pacific is making reamers 3.5 thou over case body size if that applies to the BR?

Hears what I am thinking. Turn D2 low carb to 10 thou larger than actual finished size. Cut 4 flutes on the mill with a dividing head. Heat treat. Then grind to final size on the lathe. All between centers. Not too complicated but very time consuming yes.

Anyone know what this reamer will run $ wise, resale value?
Stephen
 
PTG has a price list. As far as reselling goes it is, as everything else, worth what you can get for it. In general, a 20% discount is not enough to get a person to buy used instead of new.
When you mill the flutes on your reamer, be sure and stagger them an mind that they are ahead of center. You may set all .002 or3 ahead of center and stagger the angles (ie. 90, 91, 92, 89) or you may stagger them by setting each edge at a different distance ahead of center (ie, .002, .004, .006 etc.). If you can find a copy of W.F. Vickery's Advanced Gunsmithing, he describes making reamers pretty well with 1950's technology. Regards, Bill.
 
Since you are into it, make it a 6 flute (I think they may finish cut smoother)

Back in 1966-67 I worked for a reamer maker in New Mexico. He turned his reamer blanks 20 thou over final dimension to allow sufficient clean up on grinding. Warpage is a factor. He made all roughing reamers 4 flute, all finishing reamers 6 flute. I don't know how much stagger, it was built in to the jig holding the reamer for fluting.
 
6 flute thanks. Maybe no stagger because of the extra flutes.
I did find a spec. sheet for a 6mm PPC reamer today but I cant find the casing specs. Just to see how they relate dimentionally. The ppc is vey close to the BR.
Was working on the action vice last night. Its coming allong nicely.
Thanks guys.
Stephen
 
sdeering said:
6 flute thanks. Maybe no stagger because of the extra flutes.
I did find a spec. sheet for a 6mm PPC reamer today but I cant find the casing specs. Just to see how they relate dimentionally. The ppc is vey close to the BR.
Was working on the action vice last night. Its coming allong nicely.
Thanks guys.
Stephen
Click to expand...

The PPC requires a different bolt face and a lot of brass preparation... it is a better case if you plan on using a Benchrest Custom Action and seriously compete.

Stick to the BR case...

and there still is stagger with 6 flutes...
 
Hey look what i stumbled across. Yes still dreaming. I may have found a reamer hear on CGN fingers crossed.
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