In this case it is probably more of an individual rifle thing - I have tested this load in two 9.3x62's; same bullet, same tin of AR2207 powder, both rifles Husqvarna 1600's with the same length barrels. One rifle got 2200 fps and the other 2020fps. (The chronograph I used is well tested and is quite accurate)
Interestingly, (I suppose) both rifles recorded very close to the same velocity when loaded with AR2209 loads.
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