08-09-2020, 06:04 PM
I thought it might be helpful to share some initial brass measurements before and after firing, for these first ones from my 20" faxon barrel.
I have the first 11 cases fired, from the Hornady 105 factory bthp. As from my other post I got 2664 average MV out of these.
As close as I could measure, the case of the unfired round is 1.483", pretty uniform (5 cases). The "B" datum (0.350) measures 1.181" (Saami spec is 1.190-0.007").
The fired, unsized cases came in from 1.484 (1), 1.486, most 1.487 (4), then 1.492 (3), 1.493, 1.496. Datum points (no particular order) were 1.1895, 1.190 (3), 1.1905 (3), 1.191 (5).
I set my Hornady resizing die and sized to datum (shoulder) 1.185-1.186 (about 50-50 as measured), which will be 0.003 for the smallest, to ~0.005 for the majority. The hornady die is a little tricky for me to set so I'll leave it at this -- it's pretty much where I've been re-sizing most brass for my shooting.
I resized the 5 exceeding 1.490 to 1.485, and chamfered all 11.
Now for 2 powder ladders I plan to do:
1, with CFE
1, with 2520. I debated for a bit on this one or use TAC or 8208xbr, but settled on 2520 for now.
I will be using my 103 Eldx and hornady data.
CFE, 27.0, 27.5, 28.0, 28.5, 29.0, 29.5
AA 2520, 26.5, 27.0, 27.5, 28.0, 28.5
I will graph the results and look for node MV's.
I have the first 11 cases fired, from the Hornady 105 factory bthp. As from my other post I got 2664 average MV out of these.
As close as I could measure, the case of the unfired round is 1.483", pretty uniform (5 cases). The "B" datum (0.350) measures 1.181" (Saami spec is 1.190-0.007").
The fired, unsized cases came in from 1.484 (1), 1.486, most 1.487 (4), then 1.492 (3), 1.493, 1.496. Datum points (no particular order) were 1.1895, 1.190 (3), 1.1905 (3), 1.191 (5).
I set my Hornady resizing die and sized to datum (shoulder) 1.185-1.186 (about 50-50 as measured), which will be 0.003 for the smallest, to ~0.005 for the majority. The hornady die is a little tricky for me to set so I'll leave it at this -- it's pretty much where I've been re-sizing most brass for my shooting.
I resized the 5 exceeding 1.490 to 1.485, and chamfered all 11.
Now for 2 powder ladders I plan to do:
1, with CFE
1, with 2520. I debated for a bit on this one or use TAC or 8208xbr, but settled on 2520 for now.
I will be using my 103 Eldx and hornady data.
CFE, 27.0, 27.5, 28.0, 28.5, 29.0, 29.5
AA 2520, 26.5, 27.0, 27.5, 28.0, 28.5
I will graph the results and look for node MV's.