Yes, I did get the M-16 style sight that I mentioned earlier. I didn't like it unfortunately, it sat too high on the rail, and didn't line up with the front post. Returned it for a refund... :0
What I ended up using was a BSA 40mm red-dot with integral Weaver base, mounted far forward on the rail. Works really well for Diet Coke cans at 25 meters. Lately I've been using Gamo Hunters, RWS Superdomes, and Gamo Match. Tried Beeman Perfect Rounds, and had mixed results... maybe after a tune.
I haven't done any tuning as yet to the MP514-K, but I think I will try swapping the spring guide to the rear (mentioned by another poster a couple replies up - thanks!).
I paid about $130 +s/h for mine at Pyramyd, but I think you can get them at Sportsmans Guide for $79... shucks...