Hey guys I need help with a mag reducer

I’m in MA, but I joined a gun club in RI, 30rd prebans are fine in MA but not RI, is there anyone here smarter than me that can whip up some sort of blocker to reduce my 30rds to 10?

I would rather burn my house down then put a dumb looking 10rd mag on my gun, call me vain, or call me angel, in the morning angel (sorry for the old man reference if you don’t get it)