driftrider,
I read an article in either, Outdoor Life or American Hunter, and for the life of me I can't find that article, it was about the new primer from Remington. They called it a 209-4, I believe.

The article said the other 209 primers pushed the load forward when fired, creating a burn ring in the chamber, which causes a problem when reloading a ML. Said it required more force to seat the next load and possibly caused some folks to not seat the load properly. The article went on to say that the Rem. primer wasn't as hot, but worked fine and did not push the load forward creating the burn ring, which makes for easier loading.

I think I explained it the way they wrote it. Sorry I don't have the article handy.
dog1