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Old 08-31-2020, 10:04 PM
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Twoboxer Twoboxer is offline
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Originally Posted by J. R. WEEMS View Post
. . . Five shot test showed 21.2 variance in the selected loads. All things being equal, what would cause this. . . .
IME, that's pretty dam low ES for a handgun.

As said earlier, the most likely reason is the relatively low case fill compared to rifle. This allows the powder in each cartridge to be positioned differently depending on how stored, loaded, and/or where in the string it is fired . . . and what you did with the handgun in between shots. This affects the burn rate.

Also "carefully crafted" doesn't tell us whether you verified equal neck tension across different cases. In rifle, that's often done by turning case necks to prevent oversizing due to thick neck walls, and either leaving carbon inside the neck or lubing to ensure easy release. This affects pre-launch pressure buildup. Such steps are not usually taken for handguns because they are largely irrelevant to group size over distances normally shot.

There are perhaps other reasons that can be pursued by looking at what many rifle shooters who carefully craft their ammo routinely use.

But I repeat, IME your ES is pretty dam good.

Last edited by Twoboxer; 08-31-2020 at 10:05 PM.
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