AO: Unfortunately, we never got a twister mag, but we did get the "Express Promag." Here is a screenshot of what was offered by Boston Paintball Supply back in 1997. From the ad, it looks like you could configured it to any way you want.
I wasn't able to find very much information on them on any of the forums, but I did notice from the two pictures that they both had the BPS Foregrip attached.
So do any of you have an Boston Paintball Supply "Express Promag" in your closet?
Take a look at the full article in the AO Archives for a price guide.
What do you guys think? Have you ever heard of this before?