Bolt Hold Open Wear
The bolt-hold-open (BHO) device is a replaceable part, so I took a picture after ~500 rounds through a new PS90. The hammer pack did not get as much wear and was about the same as previous pictures posted. The bolt hold open device gets chewed-up pretty good.
Another method of protecting the hammer pack is to get some self adhesive UHMW tape (0.0115, 10 mils thick). The UHMW (polyethylene) is very wear resistant and opaque in color.
It's available from McMaster-Carr Supply Company via mail order.
http://www.mcmaster.com
Search for 'UHMW tape" or look on page 3328. I recommend the 1" wide, 0.0115 thick, smaller strips can be cut with a scissors.
Disassembly of the stock is probably required to place it on the BHO device. I don't know if the UHMW will actually adhere to the bolt-hold-open device as well, but seems to adhere remarkably well to the hammer pack. The UHMW plastic also trims well with an Xacto knife.
Just letting others know that this is another good method of protecting the hammer pack from spent case damage. The BHO device damage concerns me less since it is replaceable and hopefully will be available from FNH in the near future.