HEAD0001
See as progressive as Tom is, he is not totally right with this statement...
Originally Posted by
Grouse45 
Smokeless powders should always be weighed by weight not volume.
Today Smokeless really no longer means that is it a powder made with a Nitrocellouse base. That is the
most generally accepted as meaning that... but two examples of Smokeless powder that do not need to be measured by 'weight'. BH-209 which is a smokeless Nirtro powder - but engineered to meter and match the pressures of real black powder.
In its pure state T7 is a
smokeless powder also and it does not require to weighed.
On the other hand
Trail Boss is a smokeless Nitro powder, engineered to be bulky and take up about the same space that a volume of BP would occupy. But is is not engineered to be a black powder sub or a direct replacement for BP because it has and uses Progessive Burning. The more pressure it build the greater pressure it can create. In a pistol with a short barrel it has limited time to develope that pressure. It really is not working effeciently in as it could.
IMR... says
Trail Boss is designed specifically for low velocity lead bullet loads suitable for Cowboy Action shooting. It is primarily a pistol powder, but has some application in rifle. It is based on a whole new technology which allows very high loading density, good flow through powder measures, stability in severe temperature variation and most importantly, additional safety to the handloader.
I am not sure they ever thought it sould be loaded by volumn.
Same for:
SR 4759
This bulky handgun powder works great in the magnums, but really shines as a reduced load propellant for rifle cartridges. It's large grain size gives good loading density for reduced loads, enhancing velocity uniformity.