From the PDF link that I supplied:
II. PERMANENT EXPORT OF FIREARMS/AMMUNITION
A. Required Documentation
1) DSP-5
2) Purchase Order
3) Import Authorization
4) DSP-83
Reloading components are classified the same as ammunition for US export purposes.
n.b. I've "heard" that Cdn import permits for inert reloading components (brass, projectiles) are easy to get.