I have one on my MP5, it's A3 compactness with the stability of an A2, really can't be beat in my opinion. You might want to consider getting an original, from DSA Arms, I've seen other brands, especially on Gunbroker.com, classic case of you get what you pay for.
and why was it that these really don't work on the '93's?
something with the buffer right?
TIA for the info...