I've been reading posts after posts and I keep reading some things that I don't understand. Can you tell me what the following terms mean?

Center Feed
Stagger Feed
Blind Magazine

I have a 12fv 22-250, what "feed is it"? I load the rounds thru the top opening. Do they make magazines that you can load outside the gun and insert from the bottom for the 22-250, like a 22mag? I realize the stock would have to have an opening cut into the stock.

Will the rubber butt pad from a 12fv synthetic stock fit a synthetic stock for a 93? If so where could I get a pad?