For those of you who buy the HD-806 True Radius PRO sear stoning jig and want to stone your own sear nose, but find that many aftermarket sears are either barely too short or are only tall enough to give you just one crack at stoning the nose into the radius, the HD-122-G Gunsmith's sear may be just what you're looking for.
It's the same EDM-machined, tool steel sear that we used in all of the Harrison Design ignition sets, but made longer from the sear pin centerline to the nose and with the nose unfinished. They typically measure .412" +/- .002". This will let the gunsmith machine and stone the sear nose to the optimum length and nose configuration to give the trigger pull characteristics that are optimum for the pistol's intended use. USGI dimensions specify a range from .402" to .405" and your finished sear must remain in that range.
Extreme Service sears are manufactured from top grade tool steel to provide precise fit and reliable, consistent function under the most demanding conditions. Each part is wire EDM'd and CNC machined for a precise +/- .0005" tolerance, heat treated to Rc 53 - 56, then honed and polished to give Extreme Service in your pistol. The sear is shaped to minimize excess material, reducing weight. The sear nose features a ground nose, suitable to be stoned to the desired shape of the purchaser.
These are for gunsmith installation and will require both machining and stoning to be ready for use. It will not drop in any 1911 until this is done.
Big Book Catalog, Issue:73, Page:119