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Old August 25, 2012, 02:31 PM   #3
Unclenick
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Join Date: March 4, 2005
Location: Ohio
Posts: 10,195
1stmar,

If you post your load and your barrel length, QuickLOAD can be used to make two different powders give you the same barrel time which should keep you in an accuracy sweet spot if you have one now, though this assumes you used the same primer for both.

A couple of differences you need to be aware of. IMR4064 and Varget are stick grain propellants, where 2230 is a double base spherical propellant. Spherical propellants are easier for most powder measures to meter to a consistent weight. On the other hand, spherical propellants are harder to ignite and many times do better with magnum primers for that reason (CCI revised their magnum primer formulation specifically for spherical propellants in 1989, and these do sometimes cut down on velocity spread for folks shooting at ranges long enough for that to matter).

IMR4064 and Varget are single-base stick grain propellants. Stick powders are typically easy to ignite (especially IMR4064), and often do best with the mildest primer you can find (currently the TulAmmo KVB7, IME, but this varies over time), especially if the charge fills the case completely. Single base powders can be a little little less sooty in their fouling. The fact they don't meter as repeatably to a particular weight is somewhat compensated for by the tendency of the more tightly packed grains in a heavier load to burn more slowly, and vice versa, so the disadvantage isn't as great as it first appears. Many guns prefer stick powders for accuracy, but this isn't a universal law and you just have to try them yourself to find out.

Note that no two powder burn rate charts seem to agree on burn rate order. This is partly because the manufacturers don't publish them for each other to see, and partly because burn rates vary some, lot to lot, and so the evaluation depends which run the chart sample was taken from. Few of the charts are assembled by actual burn rate testing, but are more often inferred from pressure and velocity curves. Here's one showing 2230 as faster than either Varget or 4064. I don't doubt that for the lots they had, this is how it appeared to be. That doesn't mean yours will match exactly.
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