I may be a junior member but am not some newbie, look at my join date, I don't post UNLESS I CAN contribute. I am not a gun writing hack. I am a combat vet who had the fortune to serve with some SAS troops. I was in their armory one day and saw a box of HP slides. When I asked their armorer what they were he replied, " those are buggered slides, they crack right through on a routine basis so we just swap them out as they crack". They kept the broken ones for inventory/logistical reasons.
Many years later I was shooting IPSC with a couple of tricked out NOVAK HiPowers, shooting factory, minor power factor ammo. I changed my recoil spring every 1K rds, and guess what I cracked a slide on one. In speaking with a browning rep I was informed that the HP was never designed to stand up to any regular abuse, (their words not mine), AND that the Hi Power had a life expectancy of fewer than 20K rds, again their words not mine.
This is REAL life experience not gun writers BS or gunshop commando BS, real world. How many of you have put better than 20k rds through yours?
As a side not I totally agree with Bob H. the FN cast frames/slides are much tougher than the original forged steel ones, ask any gunsmith who has hand checkered one! This along with the added weight in the 40 slides should really aid in the 9's longevity.