6BR what twist

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nksmfamjp

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Looking to shoot 64-70gr fb bullets in 100-300yd benchrest. Based on stability calculators, it looks like I should be using 1:12, but so many shoot 1:14. What do I need? Why? Is the Berger stability calculator wrong? Are best groups below stable?
 
IMHO, go 8 twist, zero freebore and start out with the lightest bullets you can get your hands on. The throat will go away faster than you think so with the zero freebore, it's easier to go to a heavier bullet and still get closer to the lands.
Nothing worse than finding your load with the bullet you chose and after a short time, that load won't shoot anymore cause the throat has moved and you can't get close to the lands. Plan ahead.;)
 
See these kinds of posts fairly often and wonder why you're not building a PPC. Having said that, I would build it with a 13.5 or 14 twist and a .040 or a .045 throat 1.5 degree. Your idea is pretty much old school looking at the whole combination. Might help you to go to the Super Shoot or a registered SR match and look at what you'd be competing against and build something like they're shooting, it won't be a BR and most of the guys will be shooting BT bullets. I've watched guys try to keep a BR in tune on a hot day that were pretty good hands with a PPC and they were never succesful. Unless you're the second coming of Tony Boyer don't try this.
 
pablo said:
See these kinds of posts fairly often and wonder why you're not building a PPC. Having said that, I would build it with a 13.5 or 14 twist and a .040 or a .045 throat 1.5 degree. Your idea is pretty much old school looking at the whole combination. Might help you to go to the Super Shoot or a registered SR match and look at what you'd be competing against and build something like they're shooting, it won't be a BR and most of the guys will be shooting BT bullets. I've watched guys try to keep a BR in tune on a hot day that were pretty good hands with a PPC and they were never succesful. Unless you're the second coming of Tony Boyer don't try this.
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Just like it says a 6br will be hard to compete with a ppc short range
 
I think the first thing a newer shooter needs to do is consider, is, what are your goals and intentions. Do you intend to load up the motorhome and criss-cross the country in search of hall of fame points or shooter of the year awards or do you just want to get together with your friends at your local clubs for a little friendly competition while you build up your skills?

30br for score shooting and 6ppc for group. These are pushed forth as the holy grail and nothing else will do. When I started shooting in club competition I started with a Remington in .223. I was told, sell it and go custom with the holy grail of calibers. I did not do this. I put a few dollars into upgrades, learned a lot doing it, and don’t regret a dime of it. It is now chambered in 6x45 and is my go to rifle for twice monthly 300 yard competitions. My biggest competition is two other shooters shooting .223’s. No recoil, burning minimal powder, and having a blast. Like my friend says, “all we earn is the clap”.

I have also added a Kelbly custom action chambered in 6BR for 100 yard Score matches. 14 twist shooting 64-65 gr bullets. Minimal recoil compared to the 30BR. (If I am leaving anything on the table then I figure I just need to learn to shoot better) Thought about going with an 8 twist and also shooting 105’s for 600 yard matches. The problem with this is that one rifle won’t do both very well. It will always be a compromise. I was always lead to believe for greatest accuracy, shoot the slowest twist for the bullet you wish to stabilize. I also have another rifle with a custom action 6BR, 8 twist for 600 yards.

For the original poster, if you are looking to shoot 100-300 yards, the 6BR is a good choice with a twist for you intended bullet. I have one go to load (Varget) and have never had a problem with temperature changes like I see with the ppc shooters. (Changing loads every target trying to chase their tune). I would rather shoot than prep brass, any day.

It all depends on what you are trying to achieve.
 
nksmfamjp said:
Looking to shoot 64-70gr fb bullets in 100-300yd benchrest. Based on stability calculators, it looks like I should be using 1:12, but so many shoot 1:14. What do I need? Why? Is the Berger stability calculator wrong? Are best groups below stable?
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Listen to Pablo.
 
Generally speaking, I'll go with Pablo. He's given you some good counsel. I see that you are in OH. It's possible that you are considering UBR score matches. If you are there is a little more to consider. When UBR started eleven years ago, most had shot IBS and were equipped with 30BRs. It didn't take long for some to figure out that the 30 had no advantage over a 6 or 22 since we were using caliber neutral targets. Some, like myself gravitated to the 22s, but most moved to a 6 PPC. How could you go wrong with the most accurate round on the planet? Now these eleven years later, almost no one shoots a 30. The ones that do get their share of wins, but most just don't care for the extra recoil and gun handling difficulties that go along with them. At the matches I direct we will have between 20 and 40 rifles competing on a given day. 90% are 6 PPCs. There are a few 30s, a few 22s and a few 6 BRs over a season. A 6BR rarely wins, although the BRAs have taken a few. Those of us who shoot variations of 22s get some fake wood as well. A 223 has never, in eleven years to my knowledge, won in Custom or Unlimited in a registered UBR match, although they do win now and then in Factory class. I don't recall a 223 win in Modified, but I guess it could have happened. At our matches I've not seen a slow twist 6BR win, ever. Of course, if you are shooting IBS or a range with IBS rules, forget most of what I wrote and just get a 30 BR. Depending on the rules you can't go wrong starting out with a 30BR or a 6PPC. Starting with a 6 BR is nearly guaranteeing you will rarely if ever get a first place.

Rick
 
pablo said:
See these kinds of posts fairly often and wonder why you're not building a PPC.
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Everything you are saying about PPC vs BR is probably correct. One thing you may not be considering is I’m so new to benchrest, that I don’t have anything. So, let’s assume I’m a decent shooter, but have no idea how to shoot Benchrest. I’m not winning anything at first, so a winning combination is not holding me back.

What I do have is a new rifle project. It uses a custom action. It will be easy to change barrels. So I thought why not get a barrel to try these local benchrest matches with.....6BR is a common bolt face. If I like it, I pick up a more competitive rifle.....if not, I sell off the 6BR prefit barrel and enjoy my other rifle.

So for a guy building a 6br, what twist? ....and more importantly will it have stable accuracy at 14 twist vs a 12 twist?

As an aside, it seems like I need to find someone with the right 6br reamer....I’ll bet Kelbys has one....or...
 
Since the guy that developed the round and still shoots it does so with the above mentioned 13.5”-14” twist maybe you want to go that route.
Same weight bullets that tend to be shot in PPC, everything from light to hot loads.
For short range BR the last thing you want to do is over stabilize bullets.
 
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nksmfamjp said:
Looking to shoot 64-70gr fb bullets in 100-300yd benchrest. Based on stability calculators, it looks like I should be using 1:12, but so many shoot 1:14. What do I need? Why? Is the Berger stability calculator wrong? Are best groups below stable?
Click to expand...

I'm going to sidestep the BR vs PPC stuff and get right to the twist part of your question.

It's very important to look at bullet jacket length rather than weight when you decide on twist rate. 6mm bullets for 100-300 BR are normally done on the .825 or the .790 long jackets...the finished weight is barely relevant to the twist requirements in this scenario.

.825 jackets: 1:13
.790 jackets: 1:14

My experience with very good PPC's and 6BR's is that as you get closer to 'just stabilized', things show up on target that look like tune related issues when in fact, they aren't. I believe that a bit of extra stabilization (to a point, obviously) can help with non-tune-related 'on target' issues, as well as giving making the tune up not as tempermental as the day goes on or from day to day.

Ducking my head for the flying bricks up here.....:eek: -Al
 
I've got two new barrel on the way

one is a 13 and the other a 13.5. I mostly shoot IBS Score Varmint Hunter class which is a 10 pound, 6 power scope class. Last year I had a 6 BR put together. I have been shooting one form of 30 cal or another for the 20 odd years I've been involved in IBS Score shooting so I thought just for the heck of it I'd try a 6BR. I must say, the 6 BR I have gives up nothing to a 30 BR in the HBR classes, from what I can see. I won a couple of matches with it last fall, one by 4 points and 4 exes. The other by 4 points@ 300 yds. I think the rifle I have shoots tighter in the wind than the 30's I've had do and I've had a few great ones. That barrel is a 1-14 and I shot 67gn BIB's in it, around 600 all together, testing and tuning and match. Hard to beat BIB's bullets. So, I would say go for it. The guy who won the Maine State VFS 100-200 last summer did it with an ancient 6 BR, just sayin.

Pete
 
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Nor Cal Mikie said:
IMHO, go 8 twist, zero freebore and start out with the lightest bullets you can get your hands on. The throat will go away faster than you think so with the zero freebore, it's easier to go to a heavier bullet and still get closer to the lands.
Nothing worse than finding your load with the bullet you chose and after a short time, that load won't shoot anymore cause the throat has moved and you can't get close to the lands. Plan ahead.;)
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60-70 grain 6mm bullet??Don't even try it!!

8 twist is even too fast for ANY 6mm bullet.

.
 
Al Nyhus said:
I'm going to sidestep the BR vs PPC stuff and get right to the twist part of your question.

It's very important to look at bullet jacket length rather than weight when you decide on twist rate. 6mm bullets for 100-300 BR are normally done on the .825 or the .790 long jackets...the finished weight is barely relevant to the twist requirements in this scenario.

.825 jackets: 1:13
.790 jackets: 1:14

My experience with very good PPC's and 6BR's is that as you get closer to 'just stabilized', things show up on target that look like tune related issues when in fact, they aren't. I believe that a bit of extra stabilization (to a point, obviously) can help with non-tune-related 'on target' issues, as well as giving making the tune up not as tempermental as the day goes on or from day to day.

Ducking my head for the flying bricks up here.....:eek: -Al
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No flying bricks but as an FYI, several of us are shooting .825” ( double radius 7/11 format) all winter long in upstate NY winter league crap with some pretty good aggs. (High teens-low two’s) with , pretty much 13.5” & 14” barrels.
I “think” you get into potential trouble if you go long jacket combined with lower node load densities.
Most of us are medium- higher load levels, and also several shooting LT which, given the western/ desert, drier weather guys like it, and not particularly favored for colder/wetter crap we put up with around here, does surprisingly well.....for what that’s worth.
 
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