Thread: Do powders change over time.

Loading tables have become more conservative, earlier versions of the adi book just gave bullet weight now a range of projectiles is listed with slightly different weights for each. I understand that monolithic bullets have different distortion and friction coefficents under acceleration so can understand separate data for them.
As to powder changes, they do occur as mnf is a batch process using cotton as a primary ingredient and with any natural material slight variations can occur. Processing and testing will keep these within tolerances set by the manufacturer but changing from one at the bottom of the burning rate spec to one at the top might show a variation.
Double base powders show less batch to batch variation compared to single base ones as the nitroglycerine added can be varied to fine tune the results along with the coating applied.