Just picked up a marlin model 5510 super goose, and I have a few questions about it. There's a warning on the bottom of the mag that says to use the spacer with Winchester ammo, but take it out for Remington ammo. Why is that? Also, does anyone know where to get a replacement for the spacer? The one for mine disappeared at some point. Has anyone used any other ammo like federal or anything with one of these, or know how well they work? There's also a warning (this was in the ad, not on the gun itself) not to use steel shot. Does anyone know anything about this? Thanks for the help.