http://www.rockymtbroadheads.com/03ironhead-xp.html
Try this one? I just picked up a pack, will be my first mechanicals. I'm admittedly a small fixed blade fan in favor of maximum penetration so here's the reasons i like this one over all the other mechanicals i've looked at.
1. 2 blades open with 1 1/8" cut diam. so should be dynamite for penetration.
2. The cut on contact tip, which kinda makes it a four blade, but should open up the wound channel better than a two blade slit for better blood loss?
3. NO O-RINGS!!! I just picked mine up two minutes ago and played with them, very smart head to me. Its like they a spring washer in between the blades so they have some friction, but not too much. Slicker than whale poop on an iceberg me figures.
Anyhow, i'm sure others will chime in, but that would be my vote for mechanical...my next vote would be stick to the tough fixed blade...
Good luck.
B