Does Pyrodex select compress?

ENCORE50A said:

IMO and using a WAG, I would assume you're using a volume measure for your propellant. Sometimes when loading the measure, you add more or delete more, just by simply tapping or settling it slightly. Its not that uncommon when using a volume measure, where you can also be 5grs off, just with it settling slightly if tapped. Its great that you're paying attention to the witness marks. They're used to prevent over charges and double loads. If the mark drops inside the muzzle an 1/8" or so, its just a slightly lighter load and better. Its when that mark sticks out of the barrel and how far that requires immediate attention. Some shooters tap, others don't. Try to be as consistent as you can.

By the way, it wasn't a silly question. It was a great question!

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LoveSabots said:

This is an admittedly silly question, but just a tiny mystery to me when it happens every once in a while. It happened a couple of times when we were shooting my son's CVA wolf. We mark with a sharpie where a certain load of Pyrodex is with a particular sabot and bullet, say, 80 grains of Pyrodex under a harvester and 240 grain scorpion gold. We're sure the sabot is fully seated, and make a mark on the aluminum range rod where it meets the muzzle. We shoot and shoot, mark always in same spot. But every once in a great while the mark goes in past the muzzle an eighth if even that of an inch about. What's up? We swab between shots and use harvester crush ribs, so the loading is always smooth and easy. Are these times where we without noticing gave it a little extra pressure so the sabot's base displaced a bit of powder and buried itself in the charge a touch, allowing the rod to go in a tiny bit more? I know, ridiculous question, but has us stumped because safety is a prime concern, and whenever we change loads and/or bullets we remove the old mark and make a new one just for peace of mind. Any ideas on this world pressing issue much appreciated!

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