I tried installing my BSA red dot on my tippmann straight, due to the fact that the front tension screw has a shaft that is lower than the rear one (probably why weaver mounts have the notches in em) mine wouldn't mount to the gun without a weaver mount (atleast not properly). Don't get me wrong, it works, but it doesn't sit flush on top of the gun, the front of the scope tips up slightly. Also it doesn't sit in the center of the gun, its over toward the hopper side a little. You can see for yourself in these pictures I took to illustrate.
you can compensate for it with the windage and elevation adjustments, but why be ghetto. Just spend a little money and get an adapter to mount it properly. This adapter works great, I have one myself, I just no longer use it because I now have an AR-15 carry handle with weaver mount.
http://www.specopspaintball.com/inde...ROD&ProdID=305
Offset Mount
