Shooter Buck Replacement Core

It is nearly impossible to get the bolt out of this product. I am looking to sell deer because of this. I understand it has to be very durable to stop crossbow bolts.

I bought4 of these.seems to be a difference in density.I have a couple the arrows pull out easy and a couple I cant hardly pull the arrows out.Broke an arrow off trying to pull out yesterday.

The core seems not to fit very snuggly - Removing the arrows makes the core come out

I shot at 20 yards out from my AXE 405 and now am having a hard time removing the bolt from the core. It was great at stopping a 405fps bolt but if you can't easily retrieve the bolt from the core it makes it useless to practice with. May I need to go out 50 yards for better bolt retrieval?