TC Frames

The Contender frame has two firing pins, and a selector on the exposed hammer, to allow the shooter to choose between rimfire or centerfire firing pins, or to select a safety position from which neither firing pin can strike a primer. The initial baseline design of the Contender had no central safe position on the hammer, having only centerfire and rimfire firing pin positions, each being selectable through using a screwdriver.

Three variants of the original Contender design were later developed, distinguished easily by the hammer design. The first variant has a push button selector on the hammer for choosing rimfire vs. centerfire, the second variant has a left-center-right toggle switch for selecting center fire-safe-rimfire firing pins, and the third variant has a horizontal bolt selection for choosing center fire-safe-rimfire firing pin positions. All three of these Contender variants have a cougar etched on the sides of the receiver, thereby easily distinguishing them from the later G2 Contender which has a smooth-sided receiver without an etched cougar. Some of the very earliest Contenders, those requiring a screwdriver to switch the firing pin between rimfire and centerfire, had smooth sides, without the cougar etched on the sides.[3]

The original Contender designs have an adjustable trigger, allowing the shooter to change both take-up and overtravel, permitting user selection of a range of trigger pulls ranging from a fairly heavy trigger pull suitable for carrying the pistol while hunting to a "hair trigger" suitable for long range target shooting (see accurize).[4]

Unlike the later G2 Contender, the original Contender may be safely dry-fired (provided the hammer is not drawn back from the second notch) to allow a shooter to become familiar with the trigger pull. The break-action only has to be cycled, while leaving the hammer in the second notch position, to practice dry-firing. G2's with switchable firing pins (centerfire or rimfire) can be safely dry-fired with the hammer only in the safety (center) position

Link to Wiki; https://en.wikipedia.org/wiki/Thompson/Center_Contender

Thanks for asking about rimfire use in TC frames and thanks to those that responded with answers. I have wondered about this for a long time but never got around to asking on Gary’s forum.