6mm br Norma vs 308 win.

At 300m if you don't care about feeding from a magazine the choice is crystal clear:
  • 6 BR with 105gr VLD has a 5.4" wind drift for a 10 MPH crosswind
  • 308 Win with 168gr VLD has a 7.4" wind drift for a 10 MPH crosswind
  • 6 BR has 1/2 the free recoil of 308 Win
If you care about using a cartridge that feeds perfectly from a magazine then 308 Win win:
  • 308 Win feeds perfectly from magazines and machine gun belts ;)
  • 6 BR has big magazine feeding issues (Look up 6mm Swiss Match, 6.5x47 Lapua for a solution)
Personnaly, I want and need a cartridge that feeds well from a magazine and shoot a 6x47 Lapua.
6XC and 6.5x47 Lapua might have been a better choices.

Alex
 
AlexF said:
At 300m if you don't care about feeding from a magazine the choice is crystal clear:
  • 6 BR with 105gr VLD has a 5.4" wind drift for a 10 MPH crosswind
  • 308 Win with 168gr VLD has a 7.4" wind drift for a 10 MPH crosswind
  • 6 BR has 1/2 the free recoil of 308 Win
If you care about using a cartridge that feeds perfectly from a magazine then 308 Win win:
  • 308 Win feeds perfectly from magazines and machine gun belts ;)
  • 6 BR has big magazine feeding issues (Look up 6mm Swiss Match, 6.5x47 Lapua for a solution)
Personnaly, I want and need a cartridge that feeds well from a magazine and shoot a 6x47 Lapua.
6XC and 6.5x47 Lapua might have been a better choices.

Alex
Click to expand...

Alex you might want to look at the 223 with 90gr Bergers VLD 551 BC= 5.3" drift with 10 mpg at 90 deg angle. and you can also shoot the F/TR class
manitou
 
manitou210 said:
Alex you might want to look at the 223 with 90gr Bergers VLD 551 BC= 5.3" drift with 10 mpg at 90 deg angle. and you can also shoot the F/TR class
manitou
Click to expand...

AND, you'll have a perfect explanation for the nervous twitch you'll develop from all the time trying to tune your load!

Sorry Paul, just couldn't resist!
 
the 6BR died decades ago cause it couldn't be tuned properly. At least for SR BR.

Nowadays, it is a darling of mid range everything.

The 223/90 has gone through the same growing pains. but now we have a robust receipe that uses readily available components.

the only must have for this is an accurate scale but that helps ALL reloading.

Jerry
 
I have limited exerience in the "feeding" department, but certainly had no issues wih a 6BR after I installed a spacer block in the back of the magazine on a Rem 700 action.
 
The original question was: " which of the 6mmBR or the .308 is more accurate to 300 max ". I can only comment on my personal experience - I have two similar rifles made by the same gunsmith (McPhee) and configured as follows: Rifle #1 RPA Quadlock with 29" Krieger in .308 and Rifle #2 Barnard P with 27" Krieger in 6mmBR. After a lot of load development the .308 will shoot around an inch at 300 yards. Sometimes I can group in the 0.8xx" but usually it is a bit outside of an inch so, in the main, I'd say that this is a sub half-MOA rifle that usually can print about .3 MOA and occassionally, but not often, less. The Barnard is new to me and on the first day of load development the worst group was 1.03" while the best was 0.661". Day two of load development produced comparable results with the best group getting down to 0.586". All shooting done at the same range off of a Remple with the .308 having seen perfect days while the 6mm has only seen rainy/cloudy Vancouver area weather.


So, for me the results are pretty clear - Maybe because of inherent accuracy, maybe due to decreased recoil or maybe because I believed it would be so the 6mm is the more accurate cartridge in my hands out to 300.
 
An old benchrest shooter who'd been at it for over 50yrs once told me.

Shooters group better with lighter recoiling guns.
Since the 6PPC, 6mm bullets have been made to perfection.
Barrels can be hit and miss for top grade accuracy. Many buy barrels in lots of tens, test them for accuracy, keep the best and sell the rest.

In a word, I do shoot better with the 6BR to 300 meters anytime, anyday. The case like the PPC was designed for accuracy.
The .308 was never designed as a BR cartridge or target round. It was just made to do so to fit into Issue ammo rifles and military comps.
The .308 does a very good job, but that's it. There are better choices for long range.
 
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