A New Dimension: T/C Dimension
It all started in Rochester, New Hampshire, in 1967 with Warren Center’s Contender pistol. The action was eventually fitted with a buttstock and a longer barrel to give us the Contender Carbine. In 1983 a totally new single-shot rifle called the TCR 83 was introduced, and it was later improved a bit and renamed the TCR 87. The Encore came along in 1996.
Barrels of various calibers can be interchanged, but so can the appropriate bolts and magazines for them. The system is chock full of excellent details that make the system easy to use. For example, all bolts and screws that are loosened during a switch are of captive design, which means they won’t mysteriously disappear as gun parts are prone to do. Tools required for going from one caliber to another come with the rifle.
The blued chrome-moly barrels fit both right- and left-hand receivers and are 22 inches long for standard calibers and 24 inches for magnums, all with five-groove rifling. Bolt length is the same for all cartridges, but bolt travel is modified for cartridges of various lengths by machining the bolt-stop groove in the body of the bolts to different lengths—short (.223), medium (.308), a bit longer (.30-06) and longer still (.300 Magnum). The counterbored head of the bolt contains a spring-loaded extractor and a plunger-style ejector. A cocked firing pin is indicated by protrusion of the cocking piece from the rear of the bolt shroud.
An AR Influence
Utilizing the AR-15 method of attaching the barrel allows ounces to be trimmed away by using an extremely light receiver machined from Type 7075 aluminum. The barrel is screwed into a 13/4-inch-long steel extension, which slides into the front of the receiver. The barrel is indexed to its proper position when a steel pin at the bottom of the extension engages a notch in the face of the receiver. Turning a nut—or torque collar, as T/C calls it—onto the threads of the receiver holds the barrel in place. Closing and rotating the bolt engages its locking lugs with shoulders machined into the interior surface of the barrel extension.
Utilizing the AR-15 method of attaching the barrel allows ounces to be trimmed away by using an extremely light receiver machined from Type 7075 aluminum. The barrel is screwed into a 13/4-inch-long steel extension, which slides into the front of the receiver. The barrel is indexed to its proper position when a steel pin at the bottom of the extension engages a notch in the face of the receiver. Turning a nut—or torque collar, as T/C calls it—onto the threads of the receiver holds the barrel in place. Closing and rotating the bolt engages its locking lugs with shoulders machined into the interior surface of the barrel extension.
A
conventional recoil lug is replaced by a better idea. A wide slot
machined through the bottom of the receiver ring exposes a V-shaped
surface machined into the bottom of the barrel extension. It mates with a
steel lug of the same shape rising up from the floor of the stock, and
the two are drawn tightly together when the front action bolt is
tightened. In addition to resisting recoil, the “V-within-a-V” fit
orients a barrel precisely the same each time it is removed and then
reinstalled.
Video
Sighting Arrangements
The Dimension comes with a two-piece, Weaver-style base attached to its receiver. Since points of impact will differ for barrels of different calibers, a scope with accurate repeatability of adjustments will make life easy. You simply zero the scope for one of the barrels and then record windage and elevation corrections that have to be made when the other barrel is installed. Another possibility is to have one scope zeroed for the .308 deer barrel and a scope of higher magnification zeroed for the .223 coyote barrel. Although the Weaver-style mount is renowned for its ability to return a scope quite close to zero when it is removed and reinstalled, a few confirming shots on paper before heading to the hunting grounds are still a good idea.
The Dimension comes with a two-piece, Weaver-style base attached to its receiver. Since points of impact will differ for barrels of different calibers, a scope with accurate repeatability of adjustments will make life easy. You simply zero the scope for one of the barrels and then record windage and elevation corrections that have to be made when the other barrel is installed. Another possibility is to have one scope zeroed for the .308 deer barrel and a scope of higher magnification zeroed for the .223 coyote barrel. Although the Weaver-style mount is renowned for its ability to return a scope quite close to zero when it is removed and reinstalled, a few confirming shots on paper before heading to the hunting grounds are still a good idea.
Available
at extra cost is a bridge-style mounting base, the front of which
clamps securely to slotted dovetail cuts in the top of the barrel. Its
rear end is vertically split into two parts, one of which attaches to
the receiver. To use it, the two-piece base that came attached to the
rifle is removed, and screws from the rear section are used to attach
the rear base of the bridge-style mount to the receiver. After it is
installed, a large bolt draws the two halves together.
Attaching
a scope to each barrel is convenient, but this system does position a
scope much higher off the rifle than the standard base. Because the
receiver wall is quite thin, there are not many threads in two holes
drilled and tapped for the bases, so regardless of which mounting system
is chosen, the screws should be coated with liquid thread lock prior to
installation. Otherwise they will quickly vibrate loose.