6 BRNI

[Dstroud]

The dasher norma reamer is all you need. Use a new BR lapua case that measures 1.557 for head space, when you fireform the case it will shorten to about 1.548 to 1.550, the end of the neck on the br brass is what measure the the head space, you can fireform with what ever bullet you want because the neck holds the case from going forward, after you fireform the shoulder is about .025 longer than a BRA

 

[Dstroud]

I wasn't trying to make a new case, Bart was wanting to try a BRA, I was going to have to wait 8 weeks for a reamer, so I started looking at reamer specs and the dasher norma was the closest thing I could get to it at the time. I got my BRA reamer in about 8 weeks later, called Bart and told him it was in, he said he was good with the dasher norma, that how it came about.

 

[ASbobcat]

Asbobcat,

how is that to fireform? any tricks to it? and do you drop off some powder during the summer months or do you switch powders? (temp sensitivity). that speed is impressive.

I have tried the false shoulder method and found that, while it works, it's more trouble than necessary. Now I just run virgin Lapua brass through a .266 bushing to make sure the neck is snug and seat a heavy (100gr) el-cheapo bullet to a hard jam (at least .050).
So far I've had a 100% success rate.
The beauty of the new "hybrid" case is that I found velocity exactly the same as the Dasher with 0.5 gr less powder. 36.0gr of RL17 gives 100% load density. You can compress about another 1.0gr if necessary to reach a higher node without encountering pressure issues. One of the many advantages of RL17 is that it is very forgiving near max pressure, and like N550 actually performs more consistently there as well. I used to run .001 neck tension, but found that RL17 likes .002 better.
I found the node window to be very wide ( +/- 0.3gr made very little difference) so there's no need to tweek the load for temperature variations. Contrary to some reports, I have not found RL17 to be temperature sensitive.

Bob

 

[22DASHER]

Moral of the story....Literally anything you can dream up based off a 6 BR case will shoot very, very well!

 

[ASbobcat]

I wasn't trying to make a new case, Bart was wanting to try a BRA, I was going to have to wait 8 weeks for a reamer, so I started looking at reamer specs and the dasher norma was the closest thing I could get to it at the time. I got my BRA reamer in about 8 weeks later, called Bart and told him it was in, he said he was good with the dasher norma, that how it came about.

I ordered an "off the shelf/ready to ship" Norma Dasher reamer from PT&G assuming that it had a .104 FB. When I measured my first chamber for bullet seating depth, I discovered that it had a short FB (approx .070 +/-.005). I don't know if Dave has changed that since I ordered mine last year, but it's something you want to check before you place an order.

 

[ASbobcat]

Excuse the name (I just made it up). My question is: Can a chambering very similar to the 6 BRA be made with the 6 Norma Dasher reamer run in ~.080 short? The neck would be a little different I am sure, but it may make an interesting project. What do you think? James

James,

Here are some corrections to posts I made earlier concerning "6 Norma Dasher run short". I was relying on my memory, which was a mistake at my age.

I said I had run .015 short, but forgot that I was already running a "short" Dasher. What I have ended up with is actually .030 shorter than the Dasher at the .375 shoulder datum, referencing PT&G's print. My case is .080 longer at the same datum than virgin Lapua cases.
Attached is a comparison photo. Mine is very close to BRDX, but keeps the Dasher shoulder and body taper.

 

[ASbobcat]

While searching for a BRI case that would optimize RL17 behind 105-107gr bullets, I chose a solution that essentially seems to be what this thread addresses.
I liked the capacity of the Dasher, but not the short neck. I also liked the BRDX, but not it's wider shoulder. So I ran a Dasher Norma reamer in .015" short and ended up with case capacity that is within 1gr of the Dasher but with a longer neck. I am able to use Dasher dies by grinding .015 off the bottom.
Performance is 3150 fps in a 28in Krieger with 105/107gr bullets over 36gr of RL17 in Lapua brass..
Accuracy 0.3moa and 0.1moa vertical and virtually unlimited case ( 10 reloads so far with no expansion of primer pockets) and barrel life.

Here are some important corrections to my earlier load information. The velocity was correct, but I actually ended up with better accuracy (0.2moa) at a charge of 35.4gr. Referring to my notes, I realized that pressure signs started to appear at 36.1 gr, so 35.8gr should be considered a practical maximum.
The attached chrono data are for 36.1 and 36.5gr, but if you extrapolate to 35.4gr you end up close to 3150fps.

 

[Stan Taylor]

Well James here is what I would call a 6mm Bra- Stan LOL I ran a straight 6mmbr to headspace and ran my 6mm dasher another .050 deep and this what I got about .014 longer than a 6mm Bra.PS the measurement at the shoulder junction is 1.135 long.

 

[Stan Taylor]

Well I fireform about 12 pieces of brass for the 6bra-Stan and shot 2 three shot groups at a 100yds I think it's a keeper same powder charge but 2 different seating depths the barrel will speed up I'm sure 31.1 of H4895 with federal 205 primers.PS my case is not a Alex wheeler version I don't think it matters what you make as long it is based off off the 6br case.

 

[Terry]

Wow, I just called Manson and one arrived.
Brand New 6BR improved.

 

[Stan Taylor]

Wow, I just called Manson and one arrived.
Brand New 6BR improved.

We'll I guess you will have to compare notes with me when you get it going Terry.PS you have to remember I am an old marine improvise overcome an adapt LOL.

 

[Terry]