Per the Sierra Manual.......
The 7mm TCU, like the rest of the TCU family, is based on a necked up and fireformed .223 Remington case. By far the most popular of Wes Ugalde's wildcats, the 7mm TCU has dominated the "production" category of both NRA and IHMSA silhouette competition. This should come as no surprise, since the 7mm TCU has virtually everything going for it. It is superbly accurate, and not at all finicky to load for. Its parent cases are readily (and cheaply) available, and case forming is a snap. It delivers reliable knockdown on the 200 meter rams without undue recoil. In short, it is exactly what is required for the silhouette game. The 7mm TCU is the most widely used (and still the winningest) cartridge in the "production" class today. Cases for the TCUs are formed by opening up the case necks on .223 Remington cases with a tapered expander. This is best accomplished with new, unfired brass. Frequently, .223 cases that have been reloaded a few times before forming will split at the neck during the expanding process. This can be minimized by using new cases, or by annealing older cases before attempting to expand the case mouths. The initial firing will blow the shoulders and body out to its final TCU dimensions. Once cases are formed, we strongly recommend neck sizing only, unless chambering becomes difficult. Contenders perform best when headspace is held to an absolute minimum, so great care must be taken to avoid setting the shoulder back during resizing. This simple step will extend case life, increase accuracy, and ensure reliable ignition. Silhouette shooters will find that the 140 grain Spitzer or Spitzer Boat Tail are outstanding performers for everything out to the rams. The heavier 160 grain Hollow Point or Spitzer Boat Tail will provide greater momentum for reliable knockdown on the heavier, tougher rams. Sierra produces a .284" diameter 130 grain Single Shot Pistol bullet specifically for cartridges like the 7mm TCU. Even with these lightweight, thinly jacketed bullets, the TCU is at its best on deer sized game when used in barrels not shorter than 14 inches. Although the 10 inch barrels can be just as accurate as the longer barrels, they sacrifice enough velocity to make reliable expansion somewhat questionable. Within these limitations, the 7mm TCU can be a reliable performer on deer, as long as shots are placed precisely.
http://shop.reedsammo.com/category.sc?categoryId=28http://www.castbullet.com/shooting/7tcu.htmOAL 2.475 to 2.600" and velocities from 1600 to 2300 fps, depending on bullet used.
With that being said, it sounds like one great Handi caliber!
Larry, keep up the great work and be prepared to start taking orders.
Thanks, Dinny