6BR - 6BRA - 6Dasher (and the rest of them) Hmmmmmmmmm

[Mulligan]

Just curious how much FPS a dasher gets over straight BR ?

A few years ago, I was running 36.3 gr of RL-16 in my dasher at about 3100 FPS. 35.0 of that lot was right at 3015 FPS. On blustery days, that 36 gr load brought home the win more than once.

CW

 

[Ranger188]

Just curious - If I chose to chamber in 6BRA; would I simply load 6BR cases with bullets loaded into the rifling for fireforming? Would it take more than one load to finalize fireforming?

If you choose the BRA, then buy some Alpha BRA brass and no fire forming. Done.

 

[NZ_Fclass]

Thanks for all the feedback guys. I'll probably start with an unmodified 6mmBR case and a fast twist bbl. Would you recommend an 8" twist or a 7.5" which seems to be gaining some favor? I expect to be shooting VLD type bullets that range from 103gr-108gr.

I have both - 8tw from TrueFlight and 7.5 from Criterion. Both work. I guess 7.5 gives a little more redundancy as bullets get longer for calibre.

 

[gunsandgunsmithing]

Apparently, there are two clear schools of thought. One of those being that bullet speed of one of the "improved" 6br's is worth the downsides.. I won't disagree when conditions are conducive to every possible bc/velocity edge. When the rubber meets the road on tough days, it's tough to beat bc and speed. But...as I said previously, if you pull the trigger in a switch, none of them are gonna fix that for ya...period. And no, it's not really about which one favors your mistake....by some very marginal amount. Just pull up the ballistics for yourself! From a pure accuracy standpoint, it's hard to argue against the 30° shoulder, too.

I've never found a straight 6br to stretch much at all. Most brass stretch happens at the sizing stage and that is mostly attributable to the sizing die/operation. Not knocking any of the multiple very good 6br variants at all...but the straight version just makes a lot of sense under your own parameters. If brass stretch is your concern, PM me and I'll walk you through a reamer design that pretty much eliminates it as a factor as well as why and how it does.

Ultimately, all of the 6br variants are excellent choices but if speed and bc are your primary concerns, a BRX, Dasher or my own favorite...a BRDX, are where you should look in this family of cartridges. Frankly, a BRA doesn't gain enough of anything, IMHO, to make up for the downsides, at any yardage, but particularly at the ones you mentioned as you primary ones. There's just not much to be gained from a bra, IMO. If I'm gonna improve upon an existing round, I prefer to see improvement from my effort and barrel life. The little 6BRDX is the best of all worlds, IMO. Even still, for 3-500 yard work, I'd opt for the boring straight 6br version.
Just my 2cents and I'm done now.

 

[urbanrifleman]

The advantage of the 6bra is not the speed. It is that you can shoot the 6br upper node and the brass lasts forever.

 

[Kimber.204]

Last summer I got the urge to try a 6BR or 6BRA as well.
I found a used / like new barrel in 6BRA that would screw onto my ARC Archimedes and bought it for a good price.

I'm using fireform loads for 100/200yd practice and 200/300yd matches. 105's/107's/109's over IMR-4166.
Then I use my fireformed brass for 600yd slow fire loads with 112gr Match Burners again over IMR-4166.

My 112gr load is fast enough that I could use my 6XC dope with the same bullet.....it's crazy. And it's getting that performance with 10grs less powder. No pressure signs in this barrel.

 

[Alex Wheeler]

A straight 6br is probably your best bet for your use. But in lr br the bra is king. You cant deny the amount of records that fell in very short order. If you pay attention to lr br, theres no question

 

[gunsandgunsmithing]

The advantage of the 6bra is not the speed. It is that you can shoot the 6br upper node and the brass lasts forever.

So, you're saying...it's about speed.

Frankly, 1,000fps won't fix pulling the trigger in a switch, so why would 50-100fps? Truth be told, most of the advantage of a few fps is between our ears. Not that..that doesn't matter, though. It does, if you buy into that.

 

[urbanrifleman]

So, you're saying...it's about speed.

Frankly, 1,000fps won't fix pulling the trigger in a switch, so why would 50-100fps? Truth be told, most of the advantage of a few fps is between our ears. Not that..that doesn't matter, though. It does, if you buy into that.

What? That's kind of the opposite of what I said.

 

[gunsandgunsmithing]

What? That's kind of the opposite of what I said.

And...?
I re-read my post. I consider it to be accurate.

edit....Fixed it.

 

[urbanrifleman]

And...?
I re-read my post. I consider it to be accurate.

You quoted Alex Wheeler? Soooo... I'm pretty confused. I am absolutely saying the opposite about the 6bra from what you said... The key is to shoot it like a 6br.

Hey, if you are going to have a conversation with yourself, keep me out of it.

 

[Charlie-NY]

Ahahaha - you guys are too funny and very helpful all at the same time. I think I'll start with the basics and just rebarrel in 6BR. I'll grab some Lapua cases while they're available. I can always make changes later if I find a need or desire to.

I'm thinking about a Bartlein bbl for this project, even though I currently own Shilen, Lilja, Hart, Broughton and Bartlein bbls.

Any opinions on barrels? Length & contour? I think my current stock has a #7 contour bbl IIRC.

 

[Mulligan]

Ahahaha - you guys are too funny and very helpful all at the same time. I think I'll start with the basics and just rebarrel in 6BR. I'll grab some Lapua cases while they're available. I can always make changes later if I find a need or desire to.

I'm thinking about a Bartlein bbl for this project, even though I currently own Shilen, Lilja, Hart, Broughton and Bartlein bbls.

Any opinions on barrels? Length & contour? I think my current stock has a #7 contour bbl IIRC.

28" HV barrels are the most common from my observations. I run 28 and 30" HV and 1.250" straight with good results. This is for 600 yard BR and F-Class.
CW

 

[memphistransplant]

Any will work, but you already know that.

The dasher has an extra gear the other two do not have.
For shooting in tougher conditions, the extra fuel tank is nice.
You can buy high quality brass for each with no real need to fire-form.
I have all three, I have never shot the BRA, my dashers do all the heavy lifting in F-Class and 600 yard BR for me.
CW

View attachment 1329859View attachment 1329860View attachment 1329861

Edited to add photos of my targets from the last 600 Yard F-Class match.
The Dasher is a solid performer with a bigger fuel tank.
CW

That was some fine shooting, Clay. Too bad Ninja was there to trump your X count.

 

[Mulligan]

That was some fine shooting, Clay. Too bad Ninja was there to trump your X count.

It just goes to prove, You're never really the fastest horse in the barn.........
OH, you can get lucky once in a while, but, a fella best bring his A-Game if he wants to be competitive in Ninja's sand box!
CW

 

[lawrence97]

I've got a semi-custom heavy barrel rifle built off a Rem 40X action. It sits in a McMillan stock with 2" wide forearm and has a Jewell trigger. It shoots very well in its current configuration of 22-243.

However - I've been interested in rebarreling to one of the 6BR configurations for some time now. The rifle will be used for shooting paper at 600yds and under; and mostly at 400yds which is the longest distance at my current club. I may also shoot a few PA groundhogs when it's all set up. Here's what I was thinking:

Go 6BR - quality brass more available, enough juice for <600yds, best barrel life
Go 6BRA - better design, maintain long neck, more stable brass due to the 40deg shoulder
Go 6Dasher - more HP for the heavier bullets, appears to be the best choice for 600+ if I extend my current expectations

What do you guys think?

Charlie,
I have personally chambered and played with the 3 calibers mentioned and here is what I think:

6mm BR is the easy button. Brass readily available, no fireforming required and brass will last forever. I have tried it in a neck turn and a NO turn chamber. I prefer the NO turn since I can load right out of the box and go compete. The 3 or 4 6BR barrels I have chambered have all shot in the .1-.2” range at 100 yards during load development and finding a load was very easy. I have used it for fclass and PRS with success. I mostly shoot Sierra 107’s and Berger 108’s. At 600 average accuracy for 20 shots is under 3” on a calm day.

6mm Dasher required a bit more attention during load development and seem to have a very small window where it liked to shoot. I shot a dasher when no other company was making dasher brass. I had to fireform 6mm br brass to get dasher brass. Accuracy during fireforming was ok but it did require extra bullets and primers. The good thing is dasher brass is now made by a couple of companies. I used a dasher at 200 yds and at 1000. Having the extra horsepower for 1000 yds was nice but in the end it was still a 6mm and would get blown around during an fclass match at 1000.

6mm BRA is what I thought would be the greatest 6mm. I started with a neck turn (.268) chamber and played with the components that most use for it. I used Alpha 6BRA brass, Varget, H4895, CCI 450 primers, Sierra 107’s and Berger 108’s. I was new to the chambering and dedicated time to getting it to shoot right. Mine settled around 2900-2930 fps for its node and provided some great groups. It was easier to tune than the dasher but not as easy as a straight 6BR. I found it was a bit more picky on powder charge and seating depth VS my 6BR and it was running just as fast as I run my 6BR. I also tested a NO turn 6BRA with a .274 neck and it seemed a bit easier to tune than the .268 chamber but the chronograph numbers were not as good. At 100 yards it was mostly a .3” gun with a few groups dipping into the .2” range over testing. I do like the caliber and it sounds cool when you tell someone your shooting a 6 BRAAAHHH.

The Dasher and BRA will allow you to hit the higher nodes in the 3000fps range and they do it efficiently. Hitting the node also depends on your barrel specs. I strictly use 28” HV barrels or 30” 1.25” barrels from Krieger or Brux. These two calibers can do good at 1000 but I have found that in an fclass setting which requires sighters and 20 shots for record they don’t hold up as far as vertical or wind drift. They can have very tight ES and SD at the muzzle and on the target but the environment affects them more than larger calibers at 1000 yards.

I know this is not a caliber you mentioned but during my initial testing I am really liking the 6x47 if you want to shoot a 6mm at 1000 yards. It runs comfortably in the 3030fps range and you can push it over 3100 fps. Running the slower node in the 6x47 is the same reason some pick the BRA or Dasher and run them in the slower 2800-2900 node which provides longer lasting brass.

For your needs I will echo what a few others have already suggested and recommend you get a 6mm BR and go have fun. If you want it done right get a cut rifled barrel such as Brux, Krieger or Bartlein and have it fitted to your action.

 

[6bra1k]

Charlie,
I have personally chambered and played with the 3 calibers mentioned and here is what I think:

6mm BR is the easy button. Brass readily available, no fireforming required and brass will last forever. I have tried it in a neck turn and a NO turn chamber. I prefer the NO turn since I can load right out of the box and go compete. The 3 or 4 6BR barrels I have chambered have all shot in the .1-.2” range at 100 yards during load development and finding a load was very easy. I have used it for fclass and PRS with success. I mostly shoot Sierra 107’s and Berger 108’s. At 600 average accuracy for 20 shots is under 3” on a calm day.

6mm Dasher required a bit more attention during load development and seem to have a very small window where it liked to shoot. I shot a dasher when no other company was making dasher brass. I had to fireform 6mm br brass to get dasher brass. Accuracy during fireforming was ok but it did require extra bullets and primers. The good thing is dasher brass is now made by a couple of companies. I used a dasher at 200 yds and at 1000. Having the extra horsepower for 1000 yds was nice but in the end it was still a 6mm and would get blown around during an fclass match at 1000.

6mm BRA is what I thought would be the greatest 6mm. I started with a neck turn (.268) chamber and played with the components that most use for it. I used Alpha 6BRA brass, Varget, H4895, CCI 450 primers, Sierra 107’s and Berger 108’s. I was new to the chambering and dedicated time to getting it to shoot right. Mine settled around 2900-2930 fps for its node and provided some great groups. It was easier to tune than the dasher but not as easy as a straight 6BR. I found it was a bit more picky on powder charge and seating depth VS my 6BR and it was running just as fast as I run my 6BR. I also tested a NO turn 6BRA with a .274 neck and it seemed a bit easier to tune than the .268 chamber but the chronograph numbers were not as good. At 100 yards it was mostly a .3” gun with a few groups dipping into the .2” range over testing. I do like the caliber and it sounds cool when you tell someone your shooting a 6 BRAAAHHH.

The Dasher and BRA will allow you to hit the higher nodes in the 3000fps range and they do it efficiently. Hitting the node also depends on your barrel specs. I strictly use 28” HV barrels or 30” 1.25” barrels from Krieger or Brux. These two calibers can do good at 1000 but I have found that in an fclass setting which requires sighters and 20 shots for record they don’t hold up as far as vertical or wind drift. They can have very tight ES and SD at the muzzle and on the target but the environment affects them more than larger calibers at 1000 yards.

I know this is not a caliber you mentioned but during my initial testing I am really liking the 6x47 if you want to shoot a 6mm at 1000 yards. It runs comfortably in the 3030fps range and you can push it over 3100 fps. Running the slower node in the 6x47 is the same reason some pick the BRA or Dasher and run them in the slower 2800-2900 node which provides longer lasting brass.

For your needs I will echo what a few others have already suggested and recommend you get a 6mm BR and go have fun. If you want it done right get a cut rifled barrel such as Brux, Krieger or Bartlein and have it fitted to your action.

yes but...
he said 600 yards

 

[lawrence97]

yes but...
he said 600 yards

Sorry. Please excuse my lack of attention to detail “600 yards” and disregard my post/contribution.

 

[Alex Wheeler]

The good thing is you cant go wrong if its on a BR case.

 

[Charlie-NY]

I neck turn cases for my custom varmint rigs and even turn for a few of my biggame rifles. However, I'm moving away from that process and just concentrating on using the highest quality brass and keeping specific lots of brass together. Neck turning is a bit of a PITA and hasn't shown any real benefit for my purposes. Of course, my tight-neck chambers require it but the new 6BR won't have one.

Once the Lapua brass arrives I'll look for a reamer that provides about .003" in neck clearance on the loaded round.

Thanks again for all the helpful insight from everyone.