I'm about to have a 6BR built & thought i'd choose a Kreiger barrel. now i am told that their 6 groove barrle is only available in twists of 1;13, 14, or 15. the 70-95 grain bullets i want to shoot seem to call for a 1;10 or 1;9 twist. kreiger makes a 4,four) groove for 243/6mm in 1;8, 1;9, 1;10, etc. Will the 4 groove barrel provide the accuracy most shooters would require/expect, or do I have to look to another manufacture? thanks for your input/ chaz
6mmBR- Advice needed
- Thread starter chazgreen
- Start date
Chaz,
By all means the four groove will fit your needs. Check the records set by the different Guns of the Week using Kreigers you'll find they are four groove.
One decision you'll have to make is .236, or .237 bore. Kreiger offers both. Different schools of thought, but both should shoot really well. If you buy from Bruno's you won't have a choice he orders only .237.
Same goes for contour. Make sure it will fit in whatever stock you plan on using. In a factory stock a LV contour is about it.
Give that twist question a lot of thought if you only plan on shooting up to 95 grains I'd go with the nine, but if you choose an eight you'll be able to shoot everything up to 107's.
Carefully choose the reamer you want to use. Pick your freebore lenght for the bullet you'll primarilly use. If you want a do all freebore, you can't go far wrong with an .060.
Do you want to neck turn? If not a .272 neck is the way to go.
Hope this helps.
Danny
By all means the four groove will fit your needs. Check the records set by the different Guns of the Week using Kreigers you'll find they are four groove.
One decision you'll have to make is .236, or .237 bore. Kreiger offers both. Different schools of thought, but both should shoot really well. If you buy from Bruno's you won't have a choice he orders only .237.
Same goes for contour. Make sure it will fit in whatever stock you plan on using. In a factory stock a LV contour is about it.
Give that twist question a lot of thought if you only plan on shooting up to 95 grains I'd go with the nine, but if you choose an eight you'll be able to shoot everything up to 107's.
Carefully choose the reamer you want to use. Pick your freebore lenght for the bullet you'll primarilly use. If you want a do all freebore, you can't go far wrong with an .060.
Do you want to neck turn? If not a .272 neck is the way to go.
Hope this helps.
Danny
Forum Boss
Administrator
Personally, and I don't have hard data yet, I think the 4 grooves are a bit faster and clean a little easier than the 6 grooves. The other thing to consider are 3s and 5s. PacNor is making awfully nice 3-grooves today and Schneider and Broughton are producing 5s with canted or polygon land configurations. Jason is a week or two from having his Broughton 5C gun ready to start shooting. We should learn very soon whether it delivers the promised extra velocity.
In terms of groove diameter,.237 vs. .236), we certainly have evidence that the Lapua Scenar, an otherwise excellent bullet, does not like the .237. The 6mm Scenar is "slimmer" as bullets go and perhaps it needs a tighter bore, based on Jackie Schmidt's testing with a .237.,But today I chatted with Jerry Tierney, and he has a .2368" groove dimension on his 6mm Broughton 5C barrel and it shoots the 105 Scenars really well from his 6BR Improved at 3040-3050 fps--so it remains a bit of a mystery.)
I'd make the call on twist rate based on your maximum yardage: 300m or less and I'd go 10-twist and shoot the BIB 95s from an .080 to .100 Freebore. 9-twist will let you run the Berger 95s as well.
In terms of groove diameter,.237 vs. .236), we certainly have evidence that the Lapua Scenar, an otherwise excellent bullet, does not like the .237. The 6mm Scenar is "slimmer" as bullets go and perhaps it needs a tighter bore, based on Jackie Schmidt's testing with a .237.,But today I chatted with Jerry Tierney, and he has a .2368" groove dimension on his 6mm Broughton 5C barrel and it shoots the 105 Scenars really well from his 6BR Improved at 3040-3050 fps--so it remains a bit of a mystery.)
I'd make the call on twist rate based on your maximum yardage: 300m or less and I'd go 10-twist and shoot the BIB 95s from an .080 to .100 Freebore. 9-twist will let you run the Berger 95s as well.
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.