I took a file to the back left side the ambi safety on ultra 40 doublestackI got a RIA ULTRA FS this week and gave it a workout today. Mine is the HC model. I agree with you about the ambi safety - that’s gotta go. It digs into my right hand when I’m shooting. Mine fed, fired, extracted and ejected perfectly. My only issues were four times it locked back with one round left in the mag. You have anything like this happen with yours? Probably operator error but every time at the same point? I dunno.