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I`ve ordered a 6mm Krieger barrel (1:12 twist)to be chambered in 6BR or 6BRX, mainly for hunting, but also for 300 and possibly 500 & 600m F Class. 1.Is accurate shooting at this extreme distances (500 & 600m)possible with 1:12 twist and 85-90 gr bullets? 2.What will be the best choice - 6BR or 6 BRX (if F Class at 500 & 600m is not viable, I will prefer the straight 6BR)? 3.What velocities can I expect from the 6 BR and 6 BRX respectively?
Reply with quote #2
David Stripling just shot a pending new World Record group at 600 yards using 88gr Berger LoDrag bullets in a 1:10 twist. Five shots in 1.070"!! So the answer is yes, you can do it.
Read the current feature Gun of the Week story. Gene Solyntjes uses his slow-twist 30BR with great success at 600.
But, one thing you have to consider--we've run the numbers and the 105-107gr bullets will still show less wind drift at 600 yards than nearly all the lighter bullet combinations we've come up with, from 20 BRs at 3900s to Dashers driving 80gr Fowlers.
With the lighter bullets, you may get slightly better accuracy, and you will have less transit time in the barrel, and faster flight time. All that can lead to higher scores. But the downside is getting pushed more by the wind.
Chris, you might want to consider going to 1:10 twist to shoot the 88s and 90s, and if you want to shoot the Berger 95s, a 1:9 twist is advised (though we know some Dasher shooters that are using 95s successfully in 1:10 barrels--but they've got another 100fps on tap.)
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Hi Chris here in OZ we have a lot of F Class shooters using standard 6mm br's for there short range rifle they use them back to 600 m then swithc to there heavy rifle for the longs if it is windy. if it is not to bad they will some times shoot there 6mm BR Norma back to 1000 and have an equil chance of winning as any one else as in the end if it is accurate it will come down to who can read the wind better. I have gone to the Dasher and a major gunsmith here has started to do the Dasher commercialy stocking dies and having the reamer because there is a large demand here for an improved 6mm BR. The reason he chose the Dasher was not the shoulder angle he would have rathered the BRX but the problem is Redding make off the shelf dies for the dasher and you cannot get BRX dies unless you special order them pay the $50 setup fee and then pay a premium. the Dasher and BRX are essentialy the same in ballistics and David Kiff also reccomends it as the best improved BR case. Now on to the twist if you made a BR or Dasher i would use an 8 twist as for your hunting you can use the 105gr A Max and because of the plastic tip they expand rapidly on varmints. I have a Remington 700 VLS that was a 243 and when new i had it rechambered it to a BR it has the standard 1 in 9.25 twist barrel and i mostly shoot the 55gr Sierra Blitz King it shoote .3 all the time and shoots 1 1/2" groups at 300 yards so if you have an 8 twist you can use any bullet for hunting then 105-107gr match bullets for F Class. I Know of people rechambering the same 700VLS to 6mm284 and pushing the 55gr at 4200fps if you do the sums you will be spining them less in a Dasher with an 8 twist than the 6mm284 in the 9.25 twist.
Reply with quote #4
Moderator & Wild Bill
Thanks for the advise and comments. Here in Namibia (as in South Africa) the barrel and not the action is licenced. It is quite a process to get a new licence, even if you only want to re-barrel or re-chamber. I`ve ordered the 6mm Krieger 1 in 12 twist barrel in Oct 2003, it arrived in March 2005 and I still await my licence.
I therefore do not have the luxary you lucky Americans have of just ordering a new barrel, but have to go with the 1 in 12 twist.
What do you think of a 6BRX or Dasher for added capacity and a 90gr or even the 95gr Berger VLD. I`ll be satisfied if it only works out to 500m or in calm conditions perhaps out to 600m.
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The 90/95gr bullets will not work in your 1:12 barrel, you would need 1:10 or faster.
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With a 1:12" twist, you won't be able to stabilize the 95gr Bergers, and probably not the 90s. You best bet would be something in the 77-80 gr range. I don't think you can get Jef Fowler's 80s in Namibia, so I'd recommend Lapua's 77gr HP, or the Berger 80s. In fact, if you can afford the Lapua 77gr loaded ammo, that's what I'd shoot--at least till you build up your supply of brass. Quite a few people have observed that the factory 77gr ammo shoots as well as, or better than, their handloads.