Hello tranefan, great to see another NC member, (man do I miss Wilmington & Mooresville)

Checked some Ruger forum posts, came across some stock change advice. I have the Sig556, prior to the SR, but have shot the SR, I hope this may help.
http://rugerforum.net/ruger-semi-auto/27591-sr-556-buttstock-removal.htmlWelcome to DRTV, Michael Bane, did a review of the SR556, (as well as the Sig556, which is why I bought one in 08)

, perhaps he'll chime in to offer his valuable two cents.