[IYAS9YAS]

I know a retired military guy that does his own reloading. ATF paid him a visit in person at his home demanding that he justify his purchases.

Could be because re-loading for personal use is fine, but re-loading to sell is something the ATF is very interested in. You have to have a license and pay taxes on that.

[smokingfrog]

To the best of my knowledge he is not using an unusual amount of anything.

Sounds like they might be more interested in WHAT he's reloading. I wouldn't be surprised if they had some kind of watch list for people reloading .50 BMG and other calibers that could be used for long range sniping.