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Any testing with the 6BR 40deg shoulder?

tom said:
So have one more observation I should add. Yesterday I put 35 rounds through a fresh dasher barrel, and 60 through a equally fresh bra barrel. After coming off the cleaning table I always check lands touch point/erosion. The dasher moved forward just a shy .002". The bra moved .000".

As I mention these things, keep in mind it may not prove out to actually out agg a dasher in the end. These are just observations, and I will include any negative ones also. So far everything is positive. I knew I should've got after it when Sam said it was good!

Tom
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Its gonna out agg the dasher ;) I am doing one for Leo so now the cats out of the bag.
 
HUNTER3401 said:
Myself and a couple of my shooting buddys have finally gotten reamers made for the 6BR-AI (40 degree). The Ackley chamber is made where it just "crush fits" on the neck/shoulder junction on new 6BR brass. No need to make a false shoulder, jam the bullet in the lands , or any of the hastles of making Dasher, BR-DX, BRX or the like. I am fire forming with a light load, 27.0g H4895 and an old lot of Berger 105's that dont shoot good for me. The shoulder on this reamer is a little wider than most improves for slightly more powder capacity, .463 vs .460 for most BR's and Improves. I have a barrel chambered, but weather has been bad, so no load development with it. I have been experimenting since October with a 6BR-AI I hand reamered an existing 6BR chamber barrel to make a 40 degree shoulder using a BRDX reamer I had. It has showed a lot of promis to say the least. I load develop at 500 yards now. l have had one Dasher group under an inch (.900) since I have been shooting 500 yard for a year and a a half now. I had 3 groups in a row with the AI that were .8 with 3 different powder charges! I shot it in the Feb. "Dark Corner" match and opened with a 0.892, that group I was shooting slower, I found out that match that this particular rifles' groups would open up if I shot it too fast. Anyway, I finished 2nd in group that morning , loosing by .1 inches on a 4 target agg. to Chad Jenkins, a great shooter. Note, my rifle that match was listed as a 6BR on the equipment list, but was the AI. It likes Hybrids shot anywhere between 2900- 2970fps. I can shoot them 3050 with no pressure, but the groups noticable open over 2970. I am shooting 32.3g R-15 in this barrel. Note: Use Caution: this barrel has a .237 bore. That load may cause pressure in a .236 bore, work up to it! I actually shot up to 33.0 g, with no pressure, but groups opened up. I am really liking this round, it appears to be very accurate and consistent. I went to this round because I was tired of all the hastle of making Dasher cases. It is a "no turn" .272 neck to make it even more user friendly! Samuel Hall
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Terrific post. Thank you.

I was never excited about the Dasher because of the short neck and fire-forming, so abandoned it after a very brief experience. Always wanted a BRDX, but reamers and dies vanished in the dust of the Dasher frenzy.
I'm excited all over again now. Can I use my BR headspace gages?
 
tom said:
I knew I should have jumped in the pool sooner. I made the trip to deep creek this morning, dug the target carrier and back bank out of thigh deep snow. I shot a fairly corse, double ladder. I realize it's early, but it appears to have about double the window width of the dasher. I don't believe I've ever seen a dasher have 2/10ths where the impact overlaps at 1000. The 31.0 and 31.2 look more like something I would look to find on a 1/10th ladder. If this isn't a fluke, I have no clue how this thing won't agg really good! I have quite a bit to fine tune yet, but this initial ladder looks promising to say the least.

Tom

View attachment 1001520
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Looks good Tom,
Based on your knowledge of using H4895 how much will you need to back off the charge when the temps get up in the say 80's from the test you did here?
 
ASbobcat said:
Terrific post. Thank you.

I was never excited about the Dasher because of the short neck and fire-forming, so abandoned it after a very brief experience. Always wanted a BRDX, but reamers and dies vanished in the dust of the Dasher frenzy.
I'm excited all over again now. Can I use my BR headspace gages?
Click to expand...

Yes. I have been doing them about .003"-.004" short which gives about zero headspace on a virgin lapua case. I tried different amounts of crush and I didnt care for any more than .001".
 
I have read through this thread.... I'm very interested, but I'm still not sure on what "crush" is?
Are you crushing the Neck/Shoulder junction with a die?

- pat
 
You should just feel a little drag as the bolt closes, and they still need the chamber to be clean and dry the same with the cases. They are very uniform length then. I turned the necks with a pumpkin turner and these are the best and most uniform cases i ever made. ...... jim
 
Well I took " The General Lee" out this morning to fine tune what I've been doing trying to find what it likes and what my bullet making technique is doing. My goal was to achieve a consistent low 1" groupings at 600 yards.

I believe I did just that with these load tests and each load is .2 grains different in powder charge.




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LRPV said:
James, don't shoot it out before you get to a match.
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I'm done tuning, I felt like it could use some small tweaks and it appears to have worked. My luck I've shot up all my small groups testing as usual.

Now it's onto tweaking the LG hoping for the same results.
 
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