AMR-1

[VH_man]

what could one use to make the dart stop slowly, but not penetrate so far you cant get it out? im thinking of making wide flat-tipped darts that limit penetration.

[al-xg]

Yes well either you make the tip of the dart much wider ( I've tried that before and it worked quite well until I missed the target once and hit a stone wall...) or you have to make a soft target.
I just strapped about 10 layers of card board the 30cm of polystirene then some tar coated bags with a thick sheet of insulation then some scpace with a few tar coated bags randomly placed and 1.5cm of reconsituted wood then a 2cm planck of solid wood.

... and that works fine the darts don't get damaged even when they fly all the way through they dont tend to penetrate the wood too much (although it has happened) and they can still be removed (i had to use a hammer once).

Some thing that could work would just be some thin plywood under 1cm thick with a steel back pate a few centimeters behind. The spacing would just have to be less than the length of the dart so the fins don't get damaged.