I've used mechanicals and did this year with my Dad's Q2, carbons and the First Cut expandables. bow was set at 55# I beleive.

I wasn't impressed with the penetration either because once a solid bone was hit, the tip curled and penetration was lost.

I'll likely shoot mechanicals again - just a different brand. I've never lost a deer to mechanicals, but have lost deer to fixed blades (replaceable blade)