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Rifles, Reloading, Optics, Equipment
Reloading
Scratching my head at the range with different powders
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<blockquote data-quote="Philward" data-source="post: 2605845" data-attributes="member: 92604"><p>Shot these the other day, 257WBY 115g Nos BT 3.210 coal. Same charge of powder but the red was Norma MRP and the green was IMR 7828. No idea of velocity since chrono is broken. But the powders are essentially the same in the burn chart and both manufacturers have the same charge weight range for each.</p><p>Fired the MRP first 3 rounds which were the high and left one and then 2 right on top the orange bull(the 2 orange spots). Then fired 3 7828 at the shoot and see target, first shot to left of center and the next 2 up in the white paper. Followed up with the last 2 of each string, taking a short break between each shooting. <span style="color: rgb(226, 80, 65)">Just to show difference in POI with different powders, all else the same.</span> Cases are once fired, annealed, sized, necks turned. Nosler data says 3400 velocity with 7828 at the charge weight I used.</p><p>[ATTACH]389886[/ATTACH][ATTACH]389887[/ATTACH]</p><p></p><p>MRP is heavier by volume than 7828.</p><p>Norma lists relative Velocity and relative pressure for powders, MRP being RV 89.9, RP 80.1, 7828 RV 84.3, RP 77.5. I think it's relative to IMR4350 which in the chart is the 100.0 point, so MRP should be slightly more pressure and slightly more velocity than 7828. I was using standard 7828 not 7828ssc.</p></blockquote><p></p>
[QUOTE="Philward, post: 2605845, member: 92604"] Shot these the other day, 257WBY 115g Nos BT 3.210 coal. Same charge of powder but the red was Norma MRP and the green was IMR 7828. No idea of velocity since chrono is broken. But the powders are essentially the same in the burn chart and both manufacturers have the same charge weight range for each. Fired the MRP first 3 rounds which were the high and left one and then 2 right on top the orange bull(the 2 orange spots). Then fired 3 7828 at the shoot and see target, first shot to left of center and the next 2 up in the white paper. Followed up with the last 2 of each string, taking a short break between each shooting. [COLOR=rgb(226, 80, 65)]Just to show difference in POI with different powders, all else the same.[/COLOR] Cases are once fired, annealed, sized, necks turned. Nosler data says 3400 velocity with 7828 at the charge weight I used. [ATTACH alt="20220821_152551~2.jpg"]389886[/ATTACH][ATTACH alt="20220821_153335~2.jpg"]389887[/ATTACH] MRP is heavier by volume than 7828. Norma lists relative Velocity and relative pressure for powders, MRP being RV 89.9, RP 80.1, 7828 RV 84.3, RP 77.5. I think it's relative to IMR4350 which in the chart is the 100.0 point, so MRP should be slightly more pressure and slightly more velocity than 7828. I was using standard 7828 not 7828ssc. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Scratching my head at the range with different powders
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