Comments by "ostiariusalpha" (@ostiariusalpha) on "Q&A 56: Travel, Elbonian Snipers, and Contradictions" video.

Mixed powders is kind of already a thing, that's what Hornady's Superformance rounds use. The Superformance powders you can buy are not mixed, of course, because that would be a liability on Hornady.
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@jintsuubest9331 No, you simply adjust the burn rates to suit the round. For instance, you take a powder that is appropriate to your cartridge's standard barrel length, and then mix in a safe ratio of a slightly faster burning powder (essentially acting as the "lifting charge" that JRassi mentioned). This gives the bullet a boost in muzzle velocity, but doesn't leave you with extra unburnt powder; as would happen if you mixed in a slower powder instead.
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@kirbyjohnson3756 Who was talking about different chemical properties? The discussion was about different burn rates.
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