Re: 6.5x284 loads, anything but 4831
I have done a lot of testing, primarily with two powders, H4831sc and Retumbo in both a 24" SavageLRH and a 26" Cooper52. Both have 1:8 twist barrels and the COAL to the lands with Berger Hunting 140VLD's is 3.19" and 3.16" repectively. My goal was to get .25-.5MOA at 200 yards, then confirmed at 500 yards, 5-10ES, and no pressure signs at a minimum 2950 FPS. Final testing was to confirm drop data and accuracy , rock testing out at 1000 yards. My results that achieved this is;
Both rifles: Lapua brass, FL sized, neck bushing .292", case sizing -,001", .075" out of the lands.
Savage: H4831SC, 53gr. Fed 210M, 2945FPS
Retumbo, 59gr. Fed 215, 3015FPS
Cooper: H4831SC, 53gr. Fed210M, 2965FPS
Retumbo, 59gr. Fed215, 3020FPS
Notes: Retumbo has changed the powder sometime over the last couple of years. Last two recent lots have produced 60-70 FPS more velocity than my older supply. Pressure and accuracy is the same in my rifles with this hotter formulation. To get the same original velocity to match my turrets, I had to back off the new lot by 1.5 gr. Interestingly, best accuracy and pressure was achieved by backing off on seating depth. Pressure sign were just showing at these loads but disappeared when I seated at .050" or more off the lands. Retumbo gave best ES with Fed215's, H4831sc gave best accuracy with Fed210M. Both loads will produce .5MOA for both rifles but at 500 yards, the H4831SC in the Savage and Retumbo in the Cooper indicated best accuracy with groups in the .25MOA range. I haven't tried any other powders, but I did try JLK's. They perform identically to the Bergers, but since they are harder to get hold of, I use the Bergers.
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