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6BR project

I am getting a 6 BR project done by a gunsmith, he will put a 26 inch heavy Bartien barrel, Jewel trigger, McMillian A5 stock on a Rem. action. I am looking to use it for a long range benchrest rifle under 1,000 yards, using either 105 to 107 Bergers and Matchkings. Only issue bugs me is that the twist recommended by Berger is if using 105 Hybrids, then it needs a 1 in 7 twist and the 107 Matchkings require between 1 in 7 and 1 in 8. Shall I go 1 in 7 twist? I am curious what you fellows are using for your 6 BR's and its setups and what would be your freebore, shall I go tight neck or leave as standard neck using Lapua brass. Please guide me in the right direction and yes, I am not looking to go to BRX or Dasher since I already have the Redding dies. Thanks
 
I have a 7.5" twist Brux on a regular 6BR and it shoots the 105 Hybrids just fine. I'd suggest a .272" no turn neck, but you could still do a skim turn and not have too much clearance. I have free bores from .060 to .110. They all work. The shorter ones let you shoot some of the lighter bullets with good grip. My next one will probably be right in the middle at about .090". You're going to love this little round.
 
I have a 7.5" twist Brux on a regular 6BR and it shoots the 105 Hybrids just fine. I'd suggest a .272" no turn neck, but you could still do a skim turn and not have too much clearance. I have free bores from .060 to .110. They all work. The shorter ones let you shoot some of the lighter bullets with good grip. My next one will probably be right in the middle at about .090". You're going to love this little round.
What freebore do you suggest if i only use 105 to 107 bullet weight? I assumed .272 neck, I just read that the .271 might be a little tight.
 
What freebore do you suggest if i only use 105 to 107 bullet weight? I assumed .272 neck, I just read that the .271 might be a little tight.
I use a .272 no turn neck .093 free Bore 1-8 twist
I use 107 Mk on top of Varget
If I were to do it again I would consider.104 free bore
J
 
What freebore do you suggest if i only use 105 to 107 bullet weight? I assumed .272 neck, I just read that the .271 might be a little tight.
I have a .271 that I make work by picking out lots of brass, so yes it is lil tight. I think the .104 freebore Jim suggested would be good for the 105 class of bullets. What reamers does your smith have, or are you ordering your own reamer?
 
I have a .271 that I make work by picking out lots of brass, so yes it is lil tight. I think the .104 freebore Jim suggested would be good for the 105 class of bullets. What reamers does your smith have, or are you ordering your own reamer?
I have never bought a reamer for my gunsmith to use. I will give him a call as soon as he receives my rifle on Thursday and ask what reamers he has. He mentioned he has several reamers.

As for the twist, I checked the Berger website for the 105 Hybrids, and it mentioned 1 in 7 twist. 1 in 7 to 1 in 8 for the 107 Sierra Matchkings. Since the barrel is a 26 inch, should I worry if I may be shy with a 1 in 8 twist instead of a 1 in 7.5 twist? I assume the longer barrels will help with stability. Some of you uses a 1 in 8 and works just fine, but does it really depend on what style of 105 and 107 grain bullets? VLD just needs a 1 in 8 which the Hybrid needs a 1 in 7. I like to be in the safe stability zone. Thanks guys for your responses.
 
I have never bought a reamer for my gunsmith to use. I will give him a call as soon as he receives my rifle on Thursday and ask what reamers he has. He mentioned he has several reamers.

As for the twist, I checked the Berger website for the 105 Hybrids, and it mentioned 1 in 7 twist. 1 in 7 to 1 in 8 for the 107 Sierra Matchkings. Since the barrel is a 26 inch, should I worry if I may be shy with a 1 in 8 twist instead of a 1 in 7.5 twist? I assume the longer barrels will help with stability. Some of you uses a 1 in 8 and works just fine, but does it really depend on what style of 105 and 107 grain bullets? VLD just needs a 1 in 8 which the Hybrid needs a 1 in 7. I like to be in the safe stability zone. Thanks guys for your responses.
One thing to consider is 1-7 twist will torque more than you realize. For me 1-8 is perfect as I run 107 Mk or 108 Berger or even 105 VLD not everyone has luck with Hybrids they can be frustrating to learn.
Shoot Small
Jim
 
103 to 107gn bullets will work well with a fb from 90 to 110. I recently purchased a JGS 6br reamer #1262 which has a .094” fb which I think is about perfect for 103 to 107gn pills.
I like the 1:8tw and generally run the 107 Sierra with excellent results. A 1:7.5tw is a good choice for the Hybrid and as stated above a .272 no turn is the way to go.
 
I wouldn't wrap your whole project around the hybrids. My preferred bullet is the 105 VLDH, but the Sierra 107 is right there. An 8 twist works great with these. My only 7.5 twist likes the hybrids very well. An 8 twist will also shoot 80 Gr flat bases nicely. Use Berger's calculator that takes into account velocity, temp, and altitude. I think a 7.5 or 8 would work well for you.
 
Two things, you will most likely want to upgrade your dies..I've been struggling for years using off the shelf dies..My 6mmbr Hart 1-10 twist .267 neck is fine using the old Redding dies ..The Shilen 1-8 twist 6mmBRX not so much fun using the .100 shim..& the same Redding dies..My wife Has a Brux 1-7.83 twist 6mmBRX ..Runs fine...This next one will be a Brux 1-7.5 twist 6mmBRX...We use the 105 Berger Hybrid, 107SMK & the 115 DTAC..We shoot 1K distance at about 1700 ft above sea level..I'm going to have a custom die made for the BRX..But you can use the Redding 6mmbr FL die with a shim to set it to be a BRX..It works, mine just does 4 to 5 thou more sizing to the neck than I care for..Overworks the brass & creates a lot of neck tension....Mike in Ct
 
Everyone used to shoot 105gr hybrids in 1:8 twist until a year or so ago . Till berger changed recommendation from 1:8 to 1:7.5
Many a record were shot with 1:8 so you will be fine. . .. just go 1:8 and shoot
 

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