SS?
The 410S is perfectly durable even though the frame is not stainless steel. It has an alloy frame. Genitron.com shows the weight at 28 ounces, compared to an all steel 4006 which weighs 38 ounces. Just bear in mind to lubricate the rails with grease instead of oil.
Here I quote scooter123 who comments on the issue in 2011:
"Keep it clean and use enough grease that's formulated for good retention and wetting properties. On a Sig Sauer the recomended (sic) practice is to run them quite wet with grease, enough that when the slide is assembled to the frame the excess oozes out and has to be wiped off."
From the same thread I quote Deuce Caboose his alloy framed pistol:
"Carried the 6946 for years and noticed that if the slide was relatively free of burrs, the alloy frame did not wear too badly, if, as others have mentioned, it was lubed properly. When burrs and lack of lubrication were found, the frames suffered with uneven wear and gauling (sic). Oddly enough, accuracy of each was not that different."
Please note with alloy frame 3rd gens the camming lugs will wear to a point of equilibrium and stop. Fastbolt has written regarding this on our forum. You may wish to leave a note in the box regarding this with the pistol for your great grandson when he inherits the pistol. The departed comrade 18DAI has also written about this.
My personal opinion is that the extra 10 ounces of the 4006 is not something I can feel on my hip. I cannot relate myself, YMMV.
The lighter pistol is said to recoil more, but I can't see it or feel it. I cannot relate to that at the range. Maybe if you shoot one and then immediately shoot the other one you could feel a difference comparing them, but does that affect your score? Your split times? YMMV.
The barrel will give out before the frame does.
The principle of equilibrium also applies to polymer framed pistols. The release of plasticizers from the polymer follows an exponential decay curve. The older it gets the amount of plasticizer that is outgassed reaches near zero. If you leave a Glock to your great, great grandson, you might want to include a note about that too just to set his mind at ease about shooting it.
You will love that 410S, Cougar.
Kind Regards,
BrianD