As mentioned PSG primarily uses 6"x6" steel plates as targets, at an engagement distance of 5-25m for the most part.
Even if some miracle material was invented for new targets that didn't rebound the steel shot (and didn't disintegrate after a handful of shots), lots of PSG venues are quarries and other places with hard ground/backstops and the ricochet risk would still be there.
Further, most venues require the use of fibre wads to make sure there's as little mess left behind as possible and nothing permanent. Economically priced steel cartridges have regular plastic wads (but are still more expensive than lead carts, despite what this report claims). If you're willing to pay double the normal cost you can get so called 'eco-wads' but I've no idea how long/whether they actually do disintegrate and what they disintegrate into.
Semi-auto and pump-action firearms are on the tick list of the 1972 McKay White Paper of firearms/shooting items to be banned, looks like they might have got another section checked off the list.
I suspect there's going to be a flood of FAC/S1 shotguns and non-steel proofed older guns on the market very soon
