I am disappointed that this letter came to me not the ammo manufacturer.
If they believe the pressure was too high then Federal should be involved. As it is old, they may already have proven issues with that lot for all we know.
As stated my letter to them, I have the box, the lot number even the price tag showing who sold it to me a.k.a. a local LGS.
I feel your pain, but I do not believe that S&W has any liability to contact the ammo maker. They examined the gun, found nothing wrong with their product and offered to replace it at a discounted price. While that sucks, they can only control their product, not how you use it nor what ammo you load in it nor how that ammo was made.
Your effort is best spent with Federal. Anyway, I wish you best of luck finding a resolution.