RE: .410 209 Primers???
I just punched up Winchesters web site and they still only make 1 type of 209 shotgun primer .
They package it for muzzel loaders differently than what they sell for shotgun reloading, but it's the same primer.
Did the salesman try to sell you a different brand ? If he did I bet he was just trying to move a primer that dosn't sell well.
But Winchester may be coming out with a new primer.
IMO use the standard Win. 209 they have worked for me for years.