Here is a review of the Mac-10. I give credit to entenie-1995 for the instructions on the original. He's the link to the instructions. Click here to go to instructions. I made a few custom stocks. Here are some pros and cons.
-Ten round mag
-Easy to use
-Quite long range
-I had to turn the purple connectors (the purple connectors are the bullets) around so they don't shoot down instead of straight because if you don't the ram hits the top and launches it down.
-The trigger is a little messed up with two green rods but no big deal
That's the only two I could find.
So that's basically it for the Mac 10. Would be pretty good in a KNEX war. Overall, great gun. Cya