6BR vs 6BRAI !

[Ccrider]

This is another one of those priceless threads. Thanks for all the informative replies.

 

[gunsandgunsmithing]

So, the 6BR is dead?

 

[Kracken McGraw]

It's not about speed. Its about running the node you want with powder that shoots best. You want your 6br over 3000fps? CFE 223 is your powder. I have been over 3200 with it in a BRA. It's shoots too. But it's bitchy in the heat.

On the burn rate chart Ramshot Big Game is close to CFE 223, has anybody tried this with the heavier bullets in the 6BR?

 

[Fuj]

So, the 6BR is dead?

Fellow club shooter Jeremiah Keefe pulled off a 5th place overall
win at Tack Driver 3 with his 6BR. With his skills and Barts Avenger
bullets.....He would have placed higher if not for a wardrobe
malfunction. but I'll leave it at that.....

 

[ASbobcat]

I find this hard to believe, but yet I'm not saying it can't be done. Now I may take the mission on of running Quickload with every powder possible to see 3000fps out of my 6br. I do have a question, what is this comfortable pressure that you speak of, near maximum, over? Also what length of freebore is your barrel chambered too?

Quickload should NEVER be relied upon when determining maximum pressures. It is a comparison tool and useful ONLY for getting you in the ballpark for STARTING loads.
"Comfortable" load means (1) no difficult bolt lift, (2) no flattened primers and most importantly (3) no web or primer pocket diameter growth. My load is 33.5gr, which is uncompressed, and 1.5gr below the beginning any of the above listed signs of pressure (tested).
I have been shooting this load for many years and thousands of rounds, and stopped counting cycles on Lapua cases because they never wear out.
I will give you a hint, it is extruded and has a VERY unique chemistry/burn profile, common to only a very limited family of commercially available offerings. It is well documented as providing velocity increase in a wide variety of cartridges.
Freebore is .140

 

[Dgd6mm]

And I agree with some of the things you typed. I still find it hard to believe.

 

[ASbobcat]

Just curious here ! I’ve thought about a 6BRAI , but as I look at powder charge and velocity they are almost identical to 6BR. I see a lot of guys using around 30 of Varget which is the classic load for 6BR . So why switch with such a small increase in performance , if there is even one at all ?

Thx

Mark

When I began shooting the 6BR, my load was 31gr of RL-15 behind Sierra 107gr MK at 2840fps from a factory Savage 30in bbl.
When the new "Top Secret" powder became available, my velocity jumped to 3050fps from the same bbl with same cases, bullets and primers, with no loss of either accuracy or case life. Notice that the accuracy node is also very flat/forgiving. These were loaded with thrown charges from a Harrells measure. Notice also that even with relatively high ES, vertical dispersion is virtually non-existent. Groups are 5 shots at 100yds.
If you obsess over ES/SD, you will never get anywhere near this velocity with safe loads of "Extreme" powders.

 

[tom]

If the 6BR guys are getting BRA velocities, then the BRA guys can get Dasher velocities, then the Dasher guys can get 6x47 velocities, etc.......

Pretty much sums it up. If 31 grains of super secret powder is pumping out 3,000 in a BR, then 32 is 3,100 in a BRA, and 33 is 3,200 in a dasher and so on.

Coming from a competition standpoint like Sam was in his post, pretty much said what needed said. There's not much I can add really.

Tom

 

[ASbobcat]

Pretty much sums it up. If 31 grains of super secret powder is pumping out 3,000 in a BR, then 32 is 3,100 in a BRA, and 33 is 3,200 in a dasher and so on.

Coming from a competition standpoint like Sam was in his post, pretty much said what needed said. There's not much I can add really.

Tom

Yes BUT, it is not linear. As case capacity increases, efficiency decreases. I shot the Dasher for many years and burned 10% more powder to get 3% more velocity.
With the lack of availability and cost of powder, this is a consideration. There is also the consideration of barrel life.
This powder just happens to be optimized in the 6BR case at 100% load density. 3,000fps is generally accepted to be good enough out to 1,000yds.

 

[tom]

Yes BUT, it is not linear. As case capacity increases, efficiency decreases. I shot the Dasher for many years and burned 10% more powder to get 3% more velocity.
With the lack of availability and cost of powder, this is a consideration. There is also the consideration of barrel life.
This powder just happens to be optimized in the 6BR case at 100% load density. 3,000fps is generally accepted to be good enough out to 1,000yds.

Yes the diminished returns thing, I get it, that's why I've had Alex chamber zero dashers since my first BRA. Although my last Dasher did something a BRA hasn't for me, and that's a nationals win. Although that's on me, and I've out agged myself with BRA barrels. I guess that's not completely true, I got a group title at one, and one of my guns got another, but with maybe a better pilot lol.

Tom

 

[Alex Wheeler]

I'd worry more about what's winning nationals and breaking records in Benchrest. Not speeds or secret powders.

 

[bugman]

In post #9 I referenced this side of the Mississippi. I did that for a reason.

What guys can shoot and get away with out west is way different then what we can shoot over here.

Bart

Yes sir....I tried to match the speeds reported out west, and trashed some good brass. I am a slow learner. lol.

 

[kerjo]

I'd worry more about what's winning nationals and breaking records in Benchrest. Not speeds or secret powders.

Using the link Bart provided for the 600 yard nationals in Lakeland and the light gun equipment list, 30% of the top 20 in the 2 gun used a 6BR and 40% used a 6BRA. Two gun winner used a 6 Dasher.

 

[Alex Wheeler]

Don't forget the agg records.

 

[JoeDuke]

Yes BUT, it is not linear. As case capacity increases, efficiency decreases. I shot the Dasher for many years and burned 10% more powder to get 3% more velocity.
With the lack of availability and cost of powder, this is a consideration. There is also the consideration of barrel life.
This powder just happens to be optimized in the 6BR case at 100% load density. 3,000fps is generally accepted to be good enough out to 1,000yds.

I see everyone on this string being very free and open with information. Why the super secret sauce?

 

[Kracken McGraw]

I see everyone on this string being very free and open with information. Why the super secret sauce?

I’m guessing it’s the 15.5 Question, lol.

 

[padom]

Im not chasing velocity and my last 3 or 4 28" 6BR's have been in that 2850 range with 105 Bergers, 2835 107smk, no pressure issues 29.3gr H4895 and 20-30 reloads on brass. Latest is a 28" HV Bartlein 1:7.5 6mm

 

[SHall]

I see everyone on this string being very free and open with information. Why the super secret sauce?

In the words of an older BR shooter told me years ago “there ain’t no secrets to this stuff Sam.” In my opinion, if there is a secret at all it is finding a great barrel that is mated to great bullets. Those two things come in 1st and 2nd in importance. 3rd and 4th are the case (BR or Improved) and your ability to make the first three work to their full potential.

 

[Alex Wheeler]

Exactly, we are blessed with great bullets and barrels these days. The guys that know how to tune just seem to get more of those good barrels and bullets In my opinion Lr Br is a tuning contest. Yes a guy can get lucky with a great barrel, but the guys that do well consistently year after year can tune.

 

[kneedtospeed]

I feel Alex and Sam nailed it. It’s not just about speed. There’s a lot more to it. Precision Loading, tuning (harmonics), and gun handling are important factors.
The straight 6br was consistently good to me over the years at 1000 yds, with different barrels and bullets. One barrel (with 5k+ rounds) was still winning with the original 100 pieces of Lapua brass, running low velocities/pressure.
It may not shoot as tight every single day as a well tuned hotrod, but it’s easier to stay on top of the tune in changing wx, for the aggs and occasional records.