I posted a similar question on a crossbow hunting forum. I got a good response and I'll pass on the info. quoted below.

"Rambler I hunt turkeys with my bow. My dad does as well, his bow is the Exomag. We both shoot the spitfire mechanical with Zwickey Scorpio which is an arrow arrester.

You do not need to do any fixing or tinkering with the hunting heads. These arrow arresters fit over the arrow shaft by springs and has 4 wire Prods that fit behind the hunting head. With all my testing, it did not effect the arrow flight path. When the Prods come in contact with the animal or bird, they bend backwards applying pressure to the arrow shaft.

Now I have never had a pass through, even on my targets which normally if not doubbled do, I have had the arrow arresters come onto the fletching. The fletching usually stops the arrow. Last year we shot at 3 turkeys and all 3 were quick kills and no pass throughs. When the arrow stays in the body, they have trouble running or flying. Below I will give a link to a picture from a store site that shows what it is.
http://www.jakesarchery.com/product....10&pf_id=60S20

Worse case senerio with these arresters is that they will ruin the fletching, but I use feathers and have only ruined one set, my dad has not ruined any and he uses feathers as well. Veins probually will stand up better. Just remember to not pull the arrester against the grain of the feather.

If you have any more questions, please feel free to ask."