That’s an awesome issue, Ted. I’m undecided. Here's a couple samples of what I’ve read in various sites within the Federal 210 vs Federal 210M variances: Also, like Absolutely everyone while in the business, all of them have there particular viewpoints they usually kind of get inserted into thier reviews. https://winchester-large-rifle-pr01234.thenerdsblog.com/37521814/5-essential-elements-for-federal-205-primers-for-ar-15