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Rifles, Reloading, Optics, Equipment
Reloading
Top three things to reduce ES and SD
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<blockquote data-quote="Bart B" data-source="post: 659414" data-attributes="member: 5302"><p>One thing that's often overlooked when testing ammo for velocity spread from hand held rifles fired from a bench is the shooter. I've seen a few dozen fps spread in average muzzle velocity between two people shooting the same rifle and ammo. The rifle was held with different pressure averages for each shooter. And one consistantly got lower extreme spreads than the other; he held the rifle more consistant in pressure against his shoulder than the other person did. If you do your own tests, you'll probably see that the harder the rifle's held into your shoulder, the faster the bullets leave.</p><p></p><p>Reducing velocity spread as well as the spread in peak pressure does not guarantee best accuracy down range. Best example I know of was when a few US Palma Team members were developing loads for Sierra Bullets' then new 155-gr. 30 caliber bullet back in 1991. Different powders, both ball and extruded were metered (not weighed) into cases primed with Fed. 210M primers in cases weighing about 170 grains. AA2520 ball powder produced the lowest spreads in charge weight, muzzle velocity as well as peak pressure. It was also the least accurate of all powders tested. IMR4895 produced average spreads in charge weight, muzzle velocity and peak pressure but shot those bullets the most accurate.</p></blockquote><p></p>
[QUOTE="Bart B, post: 659414, member: 5302"] One thing that's often overlooked when testing ammo for velocity spread from hand held rifles fired from a bench is the shooter. I've seen a few dozen fps spread in average muzzle velocity between two people shooting the same rifle and ammo. The rifle was held with different pressure averages for each shooter. And one consistantly got lower extreme spreads than the other; he held the rifle more consistant in pressure against his shoulder than the other person did. If you do your own tests, you'll probably see that the harder the rifle's held into your shoulder, the faster the bullets leave. Reducing velocity spread as well as the spread in peak pressure does not guarantee best accuracy down range. Best example I know of was when a few US Palma Team members were developing loads for Sierra Bullets' then new 155-gr. 30 caliber bullet back in 1991. Different powders, both ball and extruded were metered (not weighed) into cases primed with Fed. 210M primers in cases weighing about 170 grains. AA2520 ball powder produced the lowest spreads in charge weight, muzzle velocity as well as peak pressure. It was also the least accurate of all powders tested. IMR4895 produced average spreads in charge weight, muzzle velocity and peak pressure but shot those bullets the most accurate. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Top three things to reduce ES and SD
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