Neck & Throat Precision Kit

The Precision Necker concept designed to enable gunsmiths to perform precise, repeatable operations quickly with a simple hand tool. The tool features a removable pilot which guides a 6-flute HSS (high-speed steel) cutter. What sets the Precision Necker apart from ordinary neck & throat reamers is its unique method of controlling depth of cut.

The straight portion of the cutter passes through a sliding bushing with a tapered shoulder at the front end. The bushing is precisely honed so that the cutter can rotate or move axially with ease, but lateral movement is virtually zero. Behind the bushing, the cutter shank is threaded with micrometer threads (40 TPI). A brass adjustment nut, backed by a knurled lock nut, controls precisely how far into the throat the cutter can reach. The adjustment nut features five equidistant grooves around its circumference each groove corresponds to .005″ of axial adjustment. Adjustments as small as .001″ can be made with confidence.

To set up the Precision Necker, gently insert the cutter into a “control” chamber (or a dummy chamber cut to the correct dimensions), turning in the “backward” (non-cutting) direction, until the cutter contacts the chamber neck. Zero the adjustment nut against the sliding bushing for a rough adjustment, then tighten a little more (forcing the cutter slightly back out of the chamber) and lock the nuts. Now cut a neck in a new chamber and measure the result. To increase the depth of cut, carefully back off the adjustment nut, lock in place, and cut again. Repeat this process until you achieve the required neck dimensions. You now have a tool set up to cut the exact same neck every time!

There is also a threaded Shank Extension available, which converts the Precision Necker to a 3/8″ (.375″ ) square drive. This drive is compatible with our Chamber Reamer T-Handle and common square-drive implements. (ordered separately)

With the included T-Handle, you can perform necking operations in barrels while they are assembled to the action/stock.

The standard shoulder angle for the Sliding Bushing is 30 degrees. In the chamber, this shoulder will contact HIGH on lesser shoulder angles (e.g. the .270 Winchester family of cartridges), and contact LOW on greater shoulder angles (e.g. 40-Degree Ackley Improved cartridges). Usually, this limited contact is adequate to control depth of cut while maintaining concentricity, but a little more care must be taken in the setup to avoid over-cutting the chamber.

Precision Neckers are available for most SAAMI cartridge specifications. This tool is designed to work on shouldered cartridges.

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