ORIGINAL: Doegirl75
Well, I had a bad case of insomnia (and boredom) last night. I was weighing triple 7 pellets on my Lyman scale when a thought occured. Do different powder measures hold the same amount of powder? So I did an experiment. I used GOEX ffg, which should be close to a 1:1 volume/weight ratio, being real black powder. I had three powder measures: a clear plastic T/C model, a solid brass one by CVA, and the speed loader from Traditions with the graduated markings. The two adjustables were set at 100grains. With each measurer, I poured 100grains worth of powder from my clear T/C flask, and then weighed the charge. I did this ten times for each measurer. Throwing out the highest and lowest readings, I got an average weight for each measurer. The T/C averaged 91.5 grains. The CVA did a bit better at 95.8 grains. The Traditions speed loader averaged in at 102.7 with the most variation in weight between charges. This is probably due to the fact that each charge had to be "eyeballed" to 100grain hash mark. This little experiment makes a strong case, in my mind, for measuring charges by weight. What y'all think?
If you weigh all your charges, you will certainly eliminate the variation in charges you'll get from merely measuring them by volume. The big question is, "will the variation you get with measured charges give you lessaccuracy thanyou'll get with weighed charges?"
It seems that the answer to this question is "not really". It has been imperically determined that when shooting BLACK POWDER that it takes at least a 5-grain variation in powder charges to cause a statistically significant variation in the muzzle velocity of the projectiles. Since what we seek for the purpose of accurate shooting is consistency, a person would have to be making an error of at least five grains of powder from one shot to the next to make any difference in the muzzle velocities of each shot, and consequently in the size of the group being shot. Even a slight difference in the pressure withwhich the bullet is seated can make a similar difference. Even the most careless among us will usually measure charges to a smaller tolerance than five grains!(I get 1750 FPS with a PRB in my .50 with 90 grains of FFg - this is only 19 FPS per grain of powder - even a five-grain error in measuring powder equals less than 100 FPS difference in MV.)
I have never weighed a powder charge for a black powder rifle, yet I have several with which I can consistently get 1" or less groups at 100 yards with PRB on a calm day.
