Yeah the Unicorn is NOT friendly to mags. A bit of sandpaper or a file on the edges of the mag well might help ease the pain but be careful not to remove much material. You just want the edges beveled.
I have to say the CYMA is earning a spot very close to my heart. Today I had the most amazing game of my life, bar none. I belly crawled through swamps, ran through ankle deep water, and dove into thick deadfall, and the CYMA didn't let me down one bit. Got some amazing kills (including a solo tower assault that left me 4-0) and the range on this thing is incredible.
Do what I did and get both guns!