Duh! I didn't read all the posts well.
I shot it blind bale from 10 yards out. Shoot it with rubber ball hanging on a string  from 10 to 35 yards. Still no pass throughs with field tips. Dont shoot broad heads at it, I think they would fly through it in a hurry. When i shoot broadheads at a deer target I use this target.

Its conveyor belting and it will stop a broadhead, but is tough to get out. An incentive not to miss  
I have two backstops of conveyor belt and one with carpet.

CKR

I'm shooting only two layers of carpet as a backstop only in front of a deer target and it stops all of my arrows.  I double over the carpet and hang it between two trees so they are loose.  Now broadheads, forget it.

If you blunt the field point just a little with a grinder, they wil never pass though the carpet.  I just use all blunts now.

we used to use the rubber matting that you put in barns that livestock lay on. works wery well.

This is good stuff guys thanks for all your ideas!

I just use a 3/4 in sheet of plywood on an angle (like a lean to ) with 2-2x4 post on the corners.Arrows that hit it glide nose down in the dirt.The tip is not to miss.  

Thanks for all the info guys.  I will make it a 4 ply loose hanging target and blunt some points if I get too much penetration.  Going to mount it between two trees and let em fly.  It's going to be a backstop and for long distance shooting so it should never get shot up but if it does I can always find some more carpet to face it with.  I will try to post picks next week when it is finished.

We use a horse stall mat from Tractor Supply. About 34 bucks. Make a frame out of 2x4 treated lumber. It's made out of very thick & tough rubber. It's 6'x4'

Haven't tried this but have a look   here .