Yeh, something I missed was that you were using mechanical heads. With that low KE (very similar to mine) they just are not reliable when discussing penetration. I noted that some others mentioned to use a NARROW cut-on-contact or replaceable blade head. That's exactly what I recommend. Personally I use either 75gr or 100gr InnerLoc's, which, determined by whatever setup I'm using in any given year. These are three-blade, 1 1/16" and 1 1/8" respectively.

Even shooting 315gr arrows at only 237fps, ringing 39ft/lbs of energy, I achieved complete passthroughs most of the time.These days I've stepped things up and shoot 330gr arrows at 260fps to 280fps and guess what. They pass through also. Just bury deeper into the ground afterward.

Another thing that means a lot is ----perfect arrow flight. No one thing is all the answers. It's a combination of all these things.