Just put these two together. Tight fit is an understatement. Took some doing before I could even get the upper on the lower. The finish of the two match absolutely perfectly.

The CAR style handguards are crazy tight. I finally managed to get them off and for awhile I thought I'd never get em back on. I always snickered at people who couldn't get M16 handguards off (and wondered what that handguard removal tool could possibly be for) but these handguards are insane.

Any tips on that?

haven't shot it yet. so far thumbs up.

Yeah, don't remove them again [:d]
Tight is good, better than loose.

I had the same experience.  The rear lug did not want to fit.  Took some pounding just to get the holes lined up.

Funny, my RRA lower is way more of a matte finish than my Model "1" upper.  Black matches black though.