Post by elkman1310 on Jul 29, 2021 17:56:39 GMT -5
I got some of the redesigned 6mm Dasher brass from Alpha. My first tests are to see what pressures and velocity it will produce compared to Lapua brass. The Alpha brass is 6 grains heavier than Lapua but the cases weigh out very close the first 40 I am working with all fell between 132.60 to 133.80grs. most were 133.20 to 133.40 the necks all run 13.2 give or take .02 which is very good and the overall length of the new cases measures 1.540 which is great .
The primer pockets are to tight for my KM or even my old RCBS primer pocket cleaner so there is no way to go in and cut a flat bottom on the primer pocket bottom. the pocket is .121 deep which is shallow the flash hole is a big .080 which I really don't like your only burning 33 grs of powder and all other brass is .062 so it puzzles me why they would go with such a big flash hole.
For my first tests I took 20 cases and trued the necks down to 12.5 and tested these in my 6mm Norma no turn chamber. I loaded up 20 cases with 450 primers and 107gr SMK bullets I loaded 32.4gr 32.6 32.8 33.0 33.2 33.4 the base of a new case measures .46895 I fired all 20 cases with my Magneto speed on the barrel I did not shoot any groups just wanted signs of pressure and velocity and compare that to Lapua brass. 32.2gr went 2890 33.4grs went 2970 which is exactly the same as a Lapua case. 32.2gr case measured .46895 and the heaviest load of 33.4grs gave a base measurement of .46905. which is really good. I anneal all the test cases and loaded 33.8grs of Varget and a 105gr JLK and shot this a 1K this morning I had 8 in 4.5 inches put I also had a high and a low shot that made the group 9 inches conditions were very good this morning and my JLK bullets have been shooting really well so the two odd balls had to from the brass . So I will have to chrony 20 cases and see what kind of SD. I am getting. So far the brass proves that their new case head is really strong I just wish that they would make it with a .062 flash hole. Lapua has it Norma has it Peterson has it Alpha doesn't that could be a problem for them.