Drop in replacement firing pin spring for Wilson Combat 1911 handguns or 1911 style handguns with hammer springs of 21# or heavier. This "Extra-Extra Power" firing pin spring will help reduce the risk of accidental discharge should the pistol be dropped. This Extra-Extra Power spring should be replaced approximately every 5,000 rounds.
Note-The use of this firing pin spring in handguns with weakened hammer springs or light hammer springs under 21# may compromise reliable ignition.
1911, Issue:10, Page:032
Big Book Catalog, Issue:67, Page:126