I picked one up at WallyWorld when I put the new sights on the Trade Rifle. Like Cayugad says, it gets you on paper at 25 yds or so. Just in the neighborhood. You can adjust from there.
It came in handy when I changed scopes on the 30-06 also.
Remember though, it doesn't guarantee accuracy, just gets you in the ballpark so you can make the adjustments at the range.