6BR- Ackley Improved 40 degree

[SHall]

It has been a monsoon here, so no time to shoot. But Stan shot the 6BR-AI at White Horse WV 600 yards this past weekend as he stated above. He said the verticle was about 1.25 inches despite a tailwind. I had only 3/4 of an inch of verticle at 500 yards going between 31.4-32.0g R-15. Thats .6g change in powder with only 3/4 inch verticle!

 

[Carolina Man]

I want one! Who has the reamer or who has a print.

George

 

[SHall]

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

 

[Eric Leonard]

IDK if it would work for the BRAI but Tim chucked a Redding FL-S Dasher bushing die in his lathe and cut enough off the bottom and made my BRDX FL-S die,,

it seems all the 105s I have tried like it best at 2920-2950 with all different powders no matter what the max speed I can get,,so it seems anything over that is a waste and your ideas on this may be the best ,easiest way to get there ,hopefully by my next barrel you will have it all sorted out,,

 

[tclaunch]

Comparing the prints, looks like you are running the BRDX in .039" to .040" to clean up the 30* shoulder. I`m no math whiz, and started comparing the datums, but with the 2 different angles I went a different route. Just curious, as this is peaking my interest with owning a lathe, and no machining background its fun!!

Revisited the prints, after thinking on it last night, more like .170" to clean up the 30* angle.

 

[saunaking]

Just got my barreled action in the stock yesterday ;D. I have 200 pieces of fire formed brass ready to go (90% using cream of wheat method). Mine has a .269 neck and .125 FB. I'm planning on starting with Varget, but do have some R15 to try as well.

 

[SHall]

Well guys, I finally got to put the 6BR-AI through it's paces in a match at Dark Corner Benchrest, their 1st 600 yard match, Jan. 2. I used the second barrel I have tried in this chambering. A HV contour Krieger 1-8 twist, .237 bore so I could use it in LG and HG. I still did not have a reamer yet so I followed a 6BR Chamber with a 40 degree shoulder BRDX reamer to just enough to make the shoulder 40 degrees. This barrel did not shoot that great as a BR, it seems the Ackey Improved shoulder brought it to life!
I was more than happy with the results. My first group was the smallest of the match, a 0.892. I ended up in LG with second place group with a 2.2 agg. Just behind Chad Jenkins with a 2.1/ Chad was on fire this match I might add, and a very good shooter. In HG it shot 3 groups in a row right around 1.9. Then I shot a 3.7 that blew me out of the top 5. I feel that group was might fault. I believe I was shooting too fast and the rifle did not have time to settle.
The load was 105 Hybrid Bergers 10 thou off rifling at 2970fps. 32.3 R-15 ( work up to this) and CCI-450's.
I have FL dies from Whidden now and have a reamer ordered from Dave Kiff at PT&G.
Sam Hall

 

[dmoran]

Sam -

Thanks for the feedback....
Impressive results and Good shooting !.!.!

Donovan

 

[Matt P]

Well guys, I finally got to put the 6BR-AI through it's paces in a match at Dark Corner Benchrest, their 1st 600 yard match, Jan. 2. I used the second barrel I have tried in this chambering. A HV contour Krieger 1-8 twist, .237 bore so I could use it in LG and HG. I still did not have a reamer yet so I followed a 6BR Chamber with a 40 degree shoulder BRDX reamer to just enough to make the shoulder 40 degrees. This barrel did not shoot that great as a BR, it seems the Ackey Improved shoulder brought it to life!
I was more than happy with the results. My first group was the smallest of the match, a 0.892. I ended up in LG with second place group with a 2.2 agg. Just behind Chad Jenkins with a 2.1/ Chad was on fire this match I might add, and a very good shooter. In HG it shot 3 groups in a row right around 1.9. Then I shot a 3.7 that blew me out of the top 5. I feel that group was might fault. I believe I was shooting too fast and the rifle did not have time to settle.
The load was 105 Hybrid Bergers 10 thou off rifling at 2970fps. 32.3 R-15 ( work up to this) and CCI-450's.
I have FL dies from Whidden now and have a reamer ordered from Dave Kiff at PT&G.
Sam Hall

Hi Sam
That load seems pretty close to the Dasher, is it hard on brass (FLS every shot)??
Matt Paroz

 

[Phil]

Nice to hear.........

 

[MarkS]

Sam,

Sounds like a good project. A lot of guys are pushing the imp's too fast. Mike, Larry, and myself were shooting the 6 BRX at 2975 f/s, when we were shooting our records. My last barrel, Mike did for me, worked out to 2975 f/s, they will run 3100 f/s, but 2975 is were they shoot. Richard Schatz shoot a Dasher, but at lower speed, we know his records. You shot a lot of your records with a 6 BR. Guys try 2975 f/s in your IMP's. The 6BR Ackley sound like a good round, it may be all the case you need. I will keep an eye on this post. Mike talked me into a 8.5 twist cut to 26", per Richard Schatz length at the time, and his speeds. This barrel is very accurate, and is very fast. I run 0.5 gr less powder with this barrel.

Mark Schronce

 

[saunaking]

I did some initial load work this fall with mine before it got too cold to really give me useful info for warm weather shooting. From info gained by another BR shooter that uses this chambering, I started at 31 grains of Varget and got up to 31.6 before finding a one-hole group at 100 yards.


This load was tested at 300 yards, with a 5 shot group under a half inch with excellent vertical. I haven't chronographed it yet, but figure my velocities are around 2900 based on 300 yard come-up. I'm using BR4 primers so far with EPS 107 grain bullets.

 

[SHall]

To answer some questions some of you have had. And to confirm what Mark S. was saying. I worked up a load well below 2970fps and up to 3050 with Berger Hybrids. The load was out of tune below 2920fps, started coming into tune between 2920-2970. Went out of tune over that velocity. I went to 3050fps but accuracy was not there. Best groups were at 2970. Even at 3050fps I did not have any case or primer pressure signs with this AI. This barrel is 29 inches long. But with a BR case, 1 inch of barrel equals about 8fps average. If it continues to shoot like it did last match I will shoot it the entire season and see how it does over the course of a year. By the way, this barrel was originally a straight BR. I worked with it a lot and never got what I considered accuracy good enough to win a match. I then just changed the case shoulder angle to 40 degrees to make an AI, and it seemed to come to life with match grade accuracy!

 

[ASbobcat]

My load in a standard 6BR with 105gr Berger's runs 2950fps (30in bbl) using 33.5gr RL17. Pressure signs don't start until about 34.5gr and I'm right at 100% load density.
I've been considering a 6BRDX because I like the long neck and feel there might be higher node just above 3000fps that I can't quite reach with a standard 6BR.
Reading this thread it sounds like it would be lot of trouble to get there, even with the 6BR-AI, and probably wouldn't accomplish much if I could.
The plain jane 6BR is just sooooooo easy.

 

[johara1]

My load in a standard 6BR with 105gr Berger's runs 2950fps (30in bbl) using 33.5gr RL17. Pressure signs don't start until about 34.5gr and I'm right at 100% load density.
I've been considering a 6BRDX because I like the long neck and feel there might be higher node just above 3000fps that I can't quite reach with a standard 6BR.
Reading this thread it sounds like it would be lot of trouble to get there, even with the 6BR-AI, and probably wouldn't accomplish much if I could.
The plain jane 6BR is just sooooooo easy.

How well does it shoot ? I have a 6BR. IMP. with a 24" barrel that is running right at 2900 with a ES of 4 with a 105 using RL- 15 that is shooting .1 groups at 100 yds. I hope the weather holds to try it at longer range..... jim

 

[ASbobcat]

How well does it shoot ? I have a 6BR. IMP. with a 24" barrel that is running right at 2900 with a ES of 4 with a 105 using RL- 15 that is shooting .1 groups at 100 yds. I hope the weather holds to try it at longer range..... jim

.1's and .2's with single digit ES.
RL17 likes full pressure and will show huge ES and SD as you begin load workup. As you approach max load those numbers will shrink dramatically. Don't give up on it too soon.
RL17 is best in long barrels due to it's long slow pressure pulse and would not be optimum in a 24" bbl. Min length to take advantage is 26" and 28"or more is better.

 

[johara1]

.1's and .2's with single digit ES.
RL17 likes full pressure and will show huge ES and SD as you begin load workup. As you approach max load those numbers will shrink dramatically. Don't give up on it too soon.
RL17 is best in long barrels due to it's long slow pressure pulse and would not be optimum in a 24" bbl. Min length to take advantage is 26" and 28"or more is better.

I never could get RL-17 to shoot good in the Dasher, it was always ok but nothing to write home about. RL-15 is an other story..... jim

 

[ASbobcat]

I never could get RL-17 to shoot good in the Dasher, it was always ok but nothing to write home about. RL-15 is an other story..... jim

Jim,
Another good thing about RL17 is that it is very forgiving when working near max pressure. Some are afraid to push the limit because of experiences they've had with scary pressure "excursions" using RL15 and other faster powders. RL17 gives plenty of warning. I stopped and backed off 1gr to the load I posted because primer pockets expanded .0005, but there was still no increase in bolt lift or ejector swipes.
Anyway, if you're happy that's all that matters.

Bob

 

[johara1]

RL-17 always shot ok but not good, i tried it in the Dasher and 6.5x47. If you are happy with it fine but it is not in the same ball park as RL-15, Varget and H4895. If you are looking for velocity i could get 3100 + with Varget and a 105 class bullet but it was a .2 load drop back to 3060 and was a .1 and under. Drop back a little more they all shot better and the bullet holes look smaller....... jim

 

[johara1]

Starting to warm up to this case. It is starting to shoot good with very limited testing first 3 shot group at 200 yds under .2........ jim