This is straight out of the 15-22 manual. It is about a page after the one year warranty section. And I understand that they don't pay much attention to the card within 30 days requirement.
Smith & Wesson’s Lifetime Service Policy begins after the warranty
period has expired. Smith & Wesson will repair, without
charge, for the lifetime of the original owner, any Smith & Wesson
handgun purchased on or after February 1, 1989, and any
M&P15 series rifle, that is found to have a defect in material or
workmanship. Eligibility for this Lifetime Service Policy requires
returning the Product Registration Card within 30 days of purchase.
The Lifetime Service Policy covers functional defects; it
does not include the firearm’s finish, grips, magazines or sights.
The Lifetime Service Policy is in addition to and not an extension
of the Smith & Wesson Warranty.