Tungsten matrix pressures are not published by Kent on their website, that I can find.
Tom Armbrust has published one pressure measurement on one loading that is right at SAAMI maximum for 12 gauge. This suggests that this ammo is suitable only in guns proofed to modern US standards.
Does anyone have further pressure tests of Kent Tungsten Matrix cartridges?
E-mail Kent and they'll tell you what the chamber pressures are. I did it a few years ago but lost the e-mail.
But even if tungsten that is used in shells that have differing alloys with differing percentages of tungsten is equal to the density of lead you don't need ultra velocity to achieve a clean kill. They killed geese before the ban.
So I don't know exactly what Kent is thinking because they produce a shell that has shot that is 'safe' to shoot in older guns but increase the chamber pressure to a point where no one will shoot Kent's shells in their older guns then you are not really marketing to people who have the older guns. Your marketing to people that have the newer guns which are already steel safe and they could care less about a safe shot to use in the shotguns. They'll say screw it and just buy the cheapest steel loads they can find.
See what I mean? So what is Kent thinking or doing? It makes absolutely no sense to me.