Re: IMR4064...why the chosen powder for
I had to get back to the house to look at everything.
The memory is a terrible thing, even worse at half-a-century.
Groups shot at 200yds.
5 rounds fired temp: 44
Load 1 2605 HIGH 2627 date: 2/11/2012
Load 2 2588 LOW 2588 bullet: 190 Nosler
Load 3 2599 AVERAGE 2607.8 OAL 2.8
Load 4 2620 MEDIAN 2605 Powder IMR 4064 42.0
Load 5 2627 STANDARD DEVIATION 15.77 text: .5" Vertical, Windy, 1.5 width
5 rounds fired temp: 44
Load 1 2603 HIGH 2621 date: 2/11/2012
Load 2 2612 LOW 2603 bullet: 190 Nosler
Load 3 2620 AVERAGE 2613.2 OAL 2.82
Load 4 2610 MEDIAN 2612 Powder Varget 42.8
Load 5 2621 STANDARD DEVIATION 7.46 text: Best group, windy conditions, spread 1.5", elevation .5"
42.5gr Varget to 43.1, 3 groups, none were over .5" tall, spread in the wind. Bolt stiffness at 44.5gr.
IMR-4064 was a node at 42.7, 43.0 43.3. 43.6 was issues with hard bolt lift, too hot.
If you notice, at ~44deg temps, the IMR-4064 might have issues when July comes around. I've never had issues with Varget's Winter-to-Summer loadings except once at OKC when it was 107deg in the shade. The load held the 10-ring but couldn't buy an X.