Best 240 to convert from 700 BDL originally 30-06

[merbeau]

Mostly I have been a Bullseye Pistol/Skeet Shooter for years and have mainly collected rifles rather than shoot them. Since moving to an area that provides more opportunity for rifle use my interest in long gun shooting has increased.
During one cold morning while reading one of my reloading magazines I came across a comment that any of the '06' family can be re barreled to the 240 Weatherby, 240 Gibbs, or 240 Hawk without having to extensively modify the bolt or magazine. The Hawk as I understand is based on the 280 case but can be formed from a 30-06 case. Further reading lead to several articles that the 6mm Norma BR is another option because of it being extremely accurate and provides extended barrel life, however, it is based on the 308 case. I believe the bolt on the 30-06 would work with a 308 case since it is a shorter 30-06 case. I would assume this would require more work in making sure the bolt locks are locked in place correctly and the head space between the bolt and barrel and cartridge is correct.
Since I do not have a rifle in any caliber less than 25 it dawned on me that perhaps a good project would be to have an older Remington 700 BDL (which was originally configured in 30-06 caliber) custom built to the 240/6mm cartridge which made sense (since I already owned a 300 Win.Mag). Another option was the family of 22 calibers, however, the 6mm appears to buck the wind better than the 22 caliber familt.
The primary use of this particular configuration is varmint, coyote and some local competitions preferring to use a 25-06 for larger game (e.g., deer, etc.).
What cartridge would be appropriate to build the custom rifle? Would building a 6mm BR just be adding extensive cost for retooling the bolt and magazine, etc.? I do reload ammunition and do not mind forming brass if it is not commercially available.

 

[hypersonic]

Mostly I have been a Bullseye Pistol/Skeet Shooter for years and have mainly collected rifles rather than shoot them. Since moving to an area that provides more opportunity for rifle use my interest in long gun shooting has increased.
During one cold morning while reading one of my reloading magazines I came across a comment that any of the '06' family can be re barreled to the 240 Weatherby, 240 Gibbs, or 240 Hawk without having to extensively modify the bolt or magazine. The Hawk as I understand is based on the 280 case but can be formed from a 30-06 case. Further reading lead to several articles that the 6mm Norma BR is another option because of it being extremely accurate and provides extended barrel life, however, it is based on the 308 case. I believe the bolt on the 30-06 would work with a 308 case since it is a shorter 30-06 case. I would assume this would require more work in making sure the bolt locks are locked in place correctly and the head space between the bolt and barrel and cartridge is correct.
Since I do not have a rifle in any caliber less than 25 it dawned on me that perhaps a good project would be to have an older Remington 700 BDL (which was originally configured in 30-06 caliber) custom built to the 240/6mm cartridge which made sense (since I already owned a 300 Win.Mag). Another option was the family of 22 calibers, however, the 6mm appears to buck the wind better than the 22 caliber familt.
The primary use of this particular configuration is varmint, coyote and some local competitions preferring to use a 25-06 for larger game (e.g., deer, etc.).
What cartridge would be appropriate to build the custom rifle? Would building a 6mm BR just be adding extensive cost for retooling the bolt and magazine, etc.? I do reload ammunition and do not mind forming brass if it is not commercially available.

If you want good performance and good barrel life you could do a 6mm Rem. With a long action you could seat high BC bullets out farther than a standandard short action would allow gaining some powder space. With the powder choices you have you might be suprised what speeds you can get out of a 26" barrel and a bullet of 100 grains or more. If you wanted a bit more you could go with an AI but the standard 6mm based on a long action and throated correctly for long bullets should make you very happy.

 

[Loner]

The 6mm Dasher is in the top of the hill right now in 1000 competition. Take a look on
the net at it.

http://www.6mmbr.com/gunweek029.html

 

[6mm Remington]

The 6mm Remington would be great in a long action. For your purposes, it would work perfectly. If you wanted to do something a little fun and different, a 6mm-06 would be a neat one also! It won't provide a lot more oomph than a standard 6mm Remington, but a bit more anyway.

6mm Remington (go for it!)

 

[rscott5028]

6br is extremely fun and easy to load for and shoot.

The '06 is Long Action and 6BR is Short Action. It will work in the LA. But, you're not taking full advantage of the cartridge.

There's no special bolt work for the 6BR. But, you do have to tweak your magazine to get it to feed nicely as a repeater. There's plenty of info available for doing that yourself.

Faster versions such as the Dasher, XC, etc may have an edge in competition at some expense for barrel life. But, it doesn't sound like you're going through 1,000's of rounds yearly anyways. And if you are, then barrels are just part of the expense.

Lapua brass is a huge plus for the 6br.

Even so, there's plenty of '06 brass that can be necked down for a 6-06' if you want something that much overbore.

In any case, you'll want to pick your target, bullet, distance, and start working back from there to design a proper shooting system. There are always compromises. But, the best ones usually have some sense of balance and purpose.

Good luck!
Richard

 

[merbeau]

First of all, thanks to all that replied.

I had not thought about the 6mm Remington. I am probably going to go with a 26 inch barrel which indeed would provide ample velocity.

I liked the idea of the BRX because of it essentially being a BR with a different shoulder. Fireforming would be not comlicated there are dies available (although custom made) and the brass is readily available.

Some of the other rounds seem to be barrel burners and while I do not shoot thousands of rounds a year, I know that I could certainly get within 1000 in several years.

I will be looking the 6mm spec closer. Thanks again for the ideas.

 

[Outlaw6.0]

I started with the exact scenario you have right now, LA 700 originally chambered in 30-06. I ended up with the 6mm-284, ballistic twin of the 6mm-06 & 240 WBY, the ability to use Lapua & Norma brass (use the Lapua) & has a background of setting a 1000yd world benchrest record (info from Sierra reloading manual).

So what does it mean? '06 bolt face (rebated rim), highest quality brass available, proven accuracy & one of the most potent 6mm's on the planet. BBL life will stink in competition i'm sure, but for LR 'yotes & Deer/goats it's hard to beat for sure.

On a side note, I also have a 6mmAI built on a Savage 110 (1-12 bbl), it is also proving to be an extremely accurate cartridge with several 3-shot groups measuring in the .3's @ 100yds (85grn bullet @3500fps). I think there is more velocity to be had, but this is a great node for me.

 

[merbeau]

High Outlaw

Thank you for replying. After a great deal of more investigation based on the comments I have received, I have pretty much zeroed in on the 6mm Ack Improved. Sure looks like your rifle will shoot.

The Ackley seems to have a longer throat which should be beter for barrel life and for longer bullets although I plan on shooting under 100 gr. projectiles. It also has some good potential accuracy as demonstrated by your post.

I used the Miller Stability coefficient to investigate barrel twist and it would appear for my application 1:10.5 would produce stabilitty from 51 to 90 grains without much problem. According to the Miller equation anything less than 1.4 would not be stable and anything above 2.0 would indicate a faster twist rate could be used. The US Military has adopted 1.5 as their thershold.

I went through 127 bullet combinations and selected those that were all 4 or 3 out of 4 are stable from 1:12 to 1:10.5 - do you have a preference?

I would probably start with the Berger 68 gr. match.

 

[Trickymissfit]

6br is extremely fun and easy to load for and shoot.

The '06 is Long Action and 6BR is Short Action. It will work in the LA. But, you're not taking full advantage of the cartridge.

There's no special bolt work for the 6BR. But, you do have to tweak your magazine to get it to feed nicely as a repeater. There's plenty of info available for doing that yourself.

Faster versions such as the Dasher, XC, etc may have an edge in competition at some expense for barrel life. But, it doesn't sound like you're going through 1,000's of rounds yearly anyways. And if you are, then barrels are just part of the expense.

Lapua brass is a huge plus for the 6br.

Even so, there's plenty of '06 brass that can be necked down for a 6-06' if you want something that much overbore.

In any case, you'll want to pick your target, bullet, distance, and start working back from there to design a proper shooting system. There are always compromises. But, the best ones usually have some sense of balance and purpose.

Good luck!
Richard

neck's too short with the Dasher, and many folks are crying because they only see three shots out of a case before it's done. I don't know as I never saw all the hype from day one. A 6BG makes it like an also run, but with good barrel life. Another to seriously think about is the old 6mm HLS, or the 6x44 built off the .300 Savage case. It seems that it's just hard to beat a generic 6BR unless you extend the case length between the base and shoulder a little bit. But if you do you loose the good neck design. Thus making your gunsmith a happy man on the way to the bank. The BG has .274" longer body and a .33" long neck. Will push a 107 grain bullet to 3000 fps without having to goto 70K psi. Next to the 6BR it's the single most efficient 24 caliber round out there
gary

 

[Trickymissfit]

I started with the exact scenario you have right now, LA 700 originally chambered in 30-06. I ended up with the 6mm-284, ballistic twin of the 6mm-06 & 240 WBY, the ability to use Lapua & Norma brass (use the Lapua) & has a background of setting a 1000yd world benchrest record (info from Sierra reloading manual).

So what does it mean? '06 bolt face (rebated rim), highest quality brass available, proven accuracy & one of the most potent 6mm's on the planet. BBL life will stink in competition i'm sure, but for LR 'yotes & Deer/goats it's hard to beat for sure.

On a side note, I also have a 6mmAI built on a Savage 110 (1-12 bbl), it is also proving to be an extremely accurate cartridge with several 3-shot groups measuring in the .3's @ 100yds (85grn bullet @3500fps). I think there is more velocity to be had, but this is a great node for me.

the world record is 2.8" and set with .300 WSM is memory is right. But it might have been with a 6.5. In 1000 yard shooting the winners are almost always a .300 mag of one kind or another (.300 Ackley seems to be the one in vogue right now). The 24 bores shoot well till a breeze comes up, and then the 30's take over.
gary

 

[Outlaw6.0]

the world record is 2.8" and set with .300 WSM is memory is right. But it might have been with a 6.5. In 1000 yard shooting the winners are almost always a .300 mag of one kind or another (.300 Ackley seems to be the one in vogue right now). The 24 bores shoot well till a breeze comes up, and then the 30's take over.
gary

I do believe you're right, IIRC the 300WSM is the record holder right now, I was just referring to the cartridges background as stated in Sierra's 5th edition.

 

[merbeau]

Hi Trickymissfit

I am a little confused. What is the difference between the 6BR and 6BG - not finding much information on this particular cartridge.

Thanks

Robert

 

[Loner]

That's one 10 shot group,(the 2.8inch) the Aggregate match record is held by Leo Anderson. His
six match score is 99.5. 10 match aggregate of 96.8. Done with a 6br improved, or Dasher as they are called. The scores are so good they may stand for decades. Hard for
shooters to take the un nerving a 300wm can dish out for that many rounds.

 

[Trickymissfit]

I do believe you're right, IIRC the 300WSM is the record holder right now, I was just referring to the cartridges background as stated in Sierra's 5th edition.

The reason those numbers stick in my head is that 2.81" group they shot! I saw a guy with a 300 Weatherby do a couple groups that were about an inch bigger, and was stunned; then this group drops in my lap!

better shooting than I could ever begin to fathom!!
gary