6BRa questions

Jcaldecott27

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Hessian
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Jan 26, 2018
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I'm currently working on getting a barrel turned for my rifle in 6BRa. What twist rate has everyone been using and im assuming 4895 is the go to powder. I'll be using 107 SMK's, and was thinking about going with a Bartlein 5r 7 twist barrel at 26". Just making sure the 7 twist barrel wont have pressure issues quicker than an 8 twist. Thanks for any information about this cartridge.
 

Krazy Korean

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Dec 6, 2018
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In a BR or BRa I would think a 7.7 or 8 twist would be enough since you won't be pushing the 110+ bullets. It's more about the bullet you shoot, and with the lower powder than a Dasher, it limits you more to the 105-108 class.
 

kthomas

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Jun 17, 2009
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I use a 28" 1:7.5 twist heavy varmint Kreiger for my 6BRA.

With 30.6 grains of H4895 I shoot a 105 Berger at ~3000 fps with no pressure issues.
 

Alpine 338

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Jun 26, 2010
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With my BRA, I'm using 110-SMKs with Varget @ around 2840-fps using a Bartlein 5R .237, 26" 7.5-twist. My barrel sped up on me 60-fps, and I had to drop 0.8-gr to get back in the node I was at before. It shot well in the faster node, but I was getting stiff bolt lift, even though no pressure signs on the cases/primers. Of course I discover this during a match where most of my misses are high, and over the target.IMG_20190408_153144425.jpgIMG_20190409_153140219.jpg
 
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ThePretzel

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Dec 17, 2017
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A 1-7 twist won't hurt you any, that's what I'm running on the BRA barrel I'm using right now (still fireforming the brass). It will allow you to shoot 115 DTACs and 110 SMKs without concerns if you decide you want to later down the road, regardless of you currently plans for bullet selection.

As far as powder goes, right now I'm just using Varget the same as in my 6BR. Gives good velocity numbers with very little deviation, and it's a known value for me as far as starting powder charges go anyways.
 

samb300

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I just had a 6BRA barrel made with a 1-7.5" twist 4-groove Bartlein. Gotta go shoot it soon, I have a bunch of H4895 on hand for it, but if that absolutely won't shoot I have Varget as well.

What is your guys go-to fireforming load for 105 Hybrids and H4895?
 

kthomas

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Jun 17, 2009
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Houston, TX
I just had a 6BRA barrel made with a 1-7.5" twist 4-groove Bartlein. Gotta go shoot it soon, I have a bunch of H4895 on hand for it, but if that absolutely won't shoot I have Varget as well.

What is your guys go-to fireforming load for 105 Hybrids and H4895?
29.5 grains H4895, Lapua brass, CCI BR4 primers, with 105 Berger's seated 5 thou off the lands.
 
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Alpine 338

Lumberjack
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My fire-forming load was with the cheapest match bullets I could find, and that is Hornady 105-gr BTHP, using Fed 105M's, and 29-gr of Reloader 15. Result was 2695-fps, and very good accuracy out to 700-yards. I wouldn't be afraid to shoot a match while fire-forming brass. I used the same load when fire-forming Dasher brass.
 

ThePretzel

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Dec 17, 2017
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Not quite the 4895 load you were looking for, but for others reading along my fireforming load with 105's is as follows:

28gr Varget
CCI BR4 Primers
105 Hybrid loaded 0.010" jammed

I found that if I used BR4's and didn't have a small jam I would get what seemed like light primer strikes, even though that shouldn't happen. Using Federal #205 primers I didn't need any jam (softer primers), but I had issues where the primers were cratering even at slow speeds that shouldn't have pressure problems.
 

arm017

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Jun 5, 2017
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Have you purchased your barrel yet OP? I would recommend a 7.5 twist. It is the goldie locks twist rate in a BR (variant) for 105-115s. IMO. That being said, I've gone 7 and 8s, and all seem to be fine regardless. I've seen the most consistency at 7.5 twist.