Odd brake drum problem

I have an 1990 honda atv. Trying install new shoes on rear brake. I have everthing backed off, but my drum won't go on over new shoes, but here is the kicker for the fun of it I put my old shoes back on and same problem. Doesn't make sense to me. I have had the drum off several times b4 and never had a problem putting back on, thank you, Brad:icon_question::