Is it safe to reload .40S&W for Glock, Walther?
I have a couple Glocks (9 & .40) and a .40 Walther P99, and I'm considering the possibility of reloading target/practice ammo for both calibers. I've been led to understand that (besides liability reasons) one of the reasons Glock has strong warnings against the use of reloaded ammo is due to the slice of unsupported case where the barrel's load ramp leads into the breech. My Walther exhibits this same characteristic. (Walther also discourages reloaded ammo, though not quite as firmly as a the Glock manual.)
Last night I was browsing a freebie "Basic Reloading Manual" courtesy of Hodgdon, IMR, and Winchester powders. When I came to the load data for .40S&W, there is a very clear warning that, "This data is intended for use in firearms with barrels which fully support the cartridge in the chamber..." (They don't show this warning explicitly with any other caliber's load data, only 40 S&W.)
So, all this has me wondering just how much of these warnings are liability protection vs. how much it might be genuinely unsafe for me to reload for these guns -- especially the .40's. Any thoughts? I am perfectly willing to carefully inspect my brass for signs of degradation, provided I know what to look for. Also, I have no need to shoot maximum loads since I would just be reloading for target/practice shooting. And although I'm new to reloading, I have strong attention to detail as well as a friend/co-worker who is a very competent reloader and trustworthy source of advice. (He reloads mostly .45 ACP and occasionally some 9mm, but not any 40S&W.)
Many thanks in advance for your wisdom and feedback!