Like all Wolff springs, these for the 1911 Auto in .45, .38 ­Super or 9mm are the finest, most reliable, longest lasting ones available. The springs of choice for most of the nation's top builders. Except where noted, all recoil springs are supplied with an extra power firing pin spring that keeps the firing pin stop in place and prevents firing pin “float”; an addition recommended by pistolsmith Bill Wilson.TYPE A - For Target (Softball) Loads were originally ­recommended to us by Major F. B. Conway, U.S.A. - M.T.U. ­Whenever lighter than standard bullets or powder charges are being used, a lighter recoil spring is a must for correct functioning; however, they MUST NOT BE USED WITH STANDARD (HARDBALL) LOADS. The 10 lb. Type A spring is the old ­favorite (for reduced loads) and for that reason we also make it available as a single item (without the extra power firing pin spring).