Spiral fluting is recommended for 5R barrels.
The Uni-Carbon Ring Removal Tool concept was developed by Dave
Kiff 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 Uni-Throater apart from ordinary
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" (.13mm) of axial adjustment. Adjustments as
small as .001" (.025mm) can be made with confidence.
The Uni-Carbon Ring Removal Tool can be used conventionally, in a
lathe. It also is threaded for attachment on our Uni-Throater T-Handle. With
the T-Handle, you can perform throating operations in barrels while they are
assembled to the action/stock. There is also a threaded Shank Extension
available, which converts the Uni-Throater to a 3/8" (.375" / 9.5mm)
square drive. This drive is compatible with our Chamber Reamer T-Handle and
common square-drive implements. This Premium Uni-Throater Kit includes both a
Uni-Throater T-Handle and threaded Shank Extension at a discount from their
individual prices.
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 overcutting the
chamber. Pacific Tool and Gauge sells replacement Sliding Bushings, and for an
extra charge we will manufacture your Sliding Bushing with a custom shoulder
angle. Refer to the Sliding Bushing product page for more information.