These were suggested to us for our indoor airgun range, but we decided against and went for airbag material instead. Stops a full power .177 or .22 rifle pellet* at 10m, (round or flat head - NOT - pointy pellets though). I believe some archery clubs use it (indoors), but I can't comment on the efficacy of it.
Milliken Ltd sell it.
* Repeated hits in the same area will cause the material to weaken. We hang a patch of heavy duty ground sheet directly behind our pellet catchers and spinners.
Kral Demon, Webley VMX, Stoeger 20, 2 x Crosman 1077's, SMK QS79, Walther Nighthawk, Walther CP99, Walther Reign, AAS200 MK1, Webley Tempest, ASG TAC Repeat, ASI Sniper (in bits). I think that's all of them - mostly shot by young people on a 10m/4 lane indoor range.