Experiment for quantifying lot to lot variations of powders

[Michael Courtney]

Mike,

The key to producing results which are meaningful is to always run what we call in science an internal control. You are right from the stand point that conditions between days will change but what you should always do is if you test say a batch of new powder, you always test a similar size batch of the old – side by side. That is your benchmark and internal control.

If there are external factors affecting the results like primer temp sensitivity, barrel, external temp, etc, they will all affect the original batch and the new batch the same way and the difference between the two is the real difference between the two batches. One has to understand that difference will not manifest itself the same manner and magnitude under different shoot conditions i.e. temps and so the difference has to be qualified with each specific condition. For example, you might not see a difference under freezing conditions but a big difference at hotter temps.

The experiments can be done even better if you shoot the two batches in a round robin manner i.e. alternate shots from the two batches. One thing I would urge you to do though is to carefully time the amount of time the chamber is allowed to cool before you single load your next round and to keep the time that round sits inside the hot chamber. If this is not consistent, the cooking effect of the hot chamber can really confound your results.

Some great points here, and we shall take care to incorporate them.