Rear Cassette Cog/Sprocket is loose
I replaced my chain on the weekend and was cleaning my bike and noticed when fitting the new chain that the top Sprocket/Cog was loose and wobbly. I noticed that this was riveted, as I thought it was screwed in. Is there a way to replace this without purchasing a whole new derailleur. I'm not sure what type to get as it's a Deore Shadow Plus 10 speed.