Manufacturing Powder

I was talking to someone yesterday that manufactures ammunition commercially and he said that Winchester 231 or HP38 is only made once a year, sometime around November.  Same goes with other powders but at different times of the year.  I don't know if this is true or not but it makes sense and might explain why my search for both of the mentioned powders have been in vain.  Make sense?

It doesn't make sense when you consider inventories required etc.. 
BUT
If the production lines are used for multiple powders and the changeover time is long and costly and outweigh the cost of inventory then yes it's probably true.

Also when you are in a sold out position of everything you produce you want the production lines down as little as possible.

- Dave

The same may be true with respect to brass casings.  I've been able to get .45 ACP but not .38 special casings from Starline.