Just drill out the flash holes to the same diameter as the main bunch, assuming they are all the same brand. If you have more than one brand (PPU are reputed to be the best Hornet brass after RWS) and one brand has small flash holes, then uniform that brand with the smallest drill that will fit all of the flash holesl. A smaller flash hole is a good thing, but mixed size flash holes in the same brand of brass is not a good thing because it leads to less than uniform velocity. However, your resizing die will stick in smaller flash holes unless you make the primer ejecting pin smaller in diameter. A well-designed flash hole tool is available from SinclairInternational in the States (this uniforms the flash hole and takes off the burr on the flash hole inside the case) but the postage is a bit eye-watering. It is all compromises, especially when trying for accuracy with the Hornet.
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