That's good and it all makes sense. The spherical powder's slow initial burn rate for progressive burning is achieved through their surface deterrent coatings. It's a good system, but it needs a minimum amount of heat and pressure to work properly, and when you don't have enough, some of the grains can extinguish or fail to ignite.
So now you've safely determined that you are dealing with a powder lot that happened to fall about in the average burn rate and energy content range. That's very good news. Now you just have to get down to more shooting.
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