6BR- Ackley Improved 40 degree

[Terry Altom]

George, I have been using two remers to make this 6BR-AI. a Std 6BR, then followed up with a 6 BRDX reamer to make the 40 degree shoulder. I am likeing what I am seeing, and Stan Taylor has actually tested it more than I have. He like what he sees also. I sent off FF brass and dimensions to Dave Kiff to have a reamer made. It will have a .269nk (be ause I have a lot of turned old cardboard boxed 6BR brass that measures .2665 with a loaded bullet).It will have a .104 fb. And Whidden is making me a FL bushing die. I sent them brass. I am at a stand still with the project until I at least get a resizing die. My brass for it needs bumping back before I shoot it any more. I thought it was interesting when I fireformed 20 pieces of brass. All 20 shots went under .309 at 100 yards. Thats a 20 shot group with some bullets that will not shoot good in anything I have ever tried them in. My Dasher usually shoots about .5 when fireforming.
James, I measured the FF brass. It averaged 1.555 after one firing. My Dasher brass draws back to 1.543 after the first fire forming. To be continued....Samuel Hall

Sam,

Are you still seeing 1.555" after multiple firings?

Thanks,
Terry

 

[SHall]

Terry, yes, basically no case overall length growth after multiple firings. Samuel

 

[Boyd L.]

I've been following this with great interest.
To someone with limited knowledge and experience with the BR and its variants such as myself this has been fascinating.
The procedure for chambering seems very complicated (again, for someone with my limitations) by utilizing one setup, but two reamers. That, along with the variations in case dimensions we've
read about that have been experimented with has me envious of the knowledge I'm reading about and wanting to know more.

Perhaps I've missed it, but has anyone specified a reamer that addresses the body diameter at the shoulder & neck dimensions that would require minimal or no turning using Lapua brass?

Just trying to learn. Thanks.

 

[22DASHER]

I've been following this with great interest.
To someone with limited knowledge and experience with the BR and its variants such as myself this has been fascinating.
The procedure for chambering seems very complicated (again, for someone with my limitations) by utilizing one setup, but two reamers. That, along with the variations in case dimensions we've
read about that have been experimented with has me envious of the knowledge I'm reading about and wanting to know more.

Perhaps I've missed it, but has anyone specified a reamer that addresses the body diameter at the shoulder & neck dimensions that would require minimal or no turning using Lapua brass?

Just trying to learn. Thanks.

http://forum.accurateshooter.com/threads/thoughts-on-6br-ai-reamer-dimensions.3916724/#post-36898968

 

[Tim Singleton]

I got my chamber cut today crown it and thread for tuner tomorrow
Have to work the weekend. Should be able to do some testing middle of the week

 

[Thumper]

Tim, what tuner do you use?

 

[Tim Singleton]

Dale Woolum's

 

[SHall]

I am resurecting the original post on the 6BR-AI, back from Sept 25, 2015. Samuel Hall

 

[Terry Altom]

Any thoughts on comparing this to a 6-BRDX? It seems with the shoulder only blown forward .039" and the availability of BRDX dies it would be a viable option to the Dasher for shorter distances.

 

[Alex Wheeler]

Any thoughts on comparing this to a 6-BRDX? It seems with the shoulder only blown forward .039" and the availability of BRDX dies it would be a viable option to the Dasher for shorter distances.

I know @tom had a brdx, and now has a 6bra. Maybe he'll chime in.

 

[tclaunch]

For whatever reason, I never did put my finger on it. I thought the dx was finicky, as soon as I went back to dashers I all of a sudden "got good barrels" again.

Tom

May have been the numbers on the reamer. I`ve had very happy guys shooting the BRDX. You met one of them.

 

[Terry Altom]

For whatever reason, I never did put my finger on it. I thought the dx was finicky, as soon as I went back to dashers I all of a sudden "got good barrels" again.

Tom

That's interesting. Just looking at it, it looks great. I would have guessed it would have been easier to load for than a Dasher. Looks like the BR-AI from Dasher shoulder dimensions will probably be the way to go.

 

[swed6.5]

Hey Tom, the velocity to powder capacity seam higher than my dasher with less powder just curious what twist barrel are you testing with?

 

[Scarab]

I have a 6brAI, 6BRDX and a dasher. I like the 6BRAI at 31.8 Varget, shoots very well from 30.9 to 32.2 gr. My DX shoots extremely well from 32.2 to 32.8 gr Varget. My dasher will only shoot when it feels like it. Even tried giving it some Midol!

 

[JamesnTN]

I have a 6brAI, 6BRDX and a dasher. I like the 6BRAI at 31.8 Varget, shoots very well from 30.9 to 32.2 gr. My DX shoots extremely well from 32.2 to 32.8 gr Varget. My dasher will only shoot when it feels like it. Even tried giving it some Midol!

That's why I call them Dasher Days

 

[johara1]

I never had a Dasher barrel not shoot if that the barrel was good. The main draw back to the Dasher is making good cases. The 6br imp. eliminates this and makes it fun again, but at 1000 i think it is worth the extra effort to make the Dasher cases. jim

 

[maddysdad]

I never had a Dasher barrel not shoot if that the barrel was good. The main draw back to the Dasher is making good cases. The 6br imp. eliminates this and makes it fun again, but at 1000 i think it is worth the extra effort to make the Dasher cases. jim

 

[Scarab]

I wasn't knocking the dasher, it has had tremendous success. For me, I feel the the the larger tune window of the AI or the DX will yield overall more consistent results with a little longer barrel and brass life. This will be my first venture shooting 600yardBR so I don't have anything to compare it to. I hope the AI works out, I had a light and heavy gun built for that cartridge.
Like tom said, the AI should be a tad bit more friendly to keep in check. Pics attached were shot in a 15-20mph wind no hold at 300 yards. Tuning was done at 100yards no hold.

 

[Terry Altom]

Is there any good/decent way to modify an existing 6BR chamber to the BR-AI without completely rechambering?

 

[JamesnTN]

Is there any good/decent way to modify an existing 6BR chamber to the BR-AI without completely rechambering?

Just run the BR AI reamer in should do it I would think