Notes: This traditional single-shot rifle was first introduced in 1966. The rifle uses a falling block action, operated by the handle which forma a part of the trigger guard. The weapon normally ejects the spent cartridge case when the handle is actuated, but this ejector may be disengaged and the spent round removed manually (presumably to facilitate recovery of the case). There is a safety catch on the neck of the stock. The mechanism is simple, strong, and compact, and can be adapted to a large number of chamberings. It should be noted that versions and chamberings of the Ruger No. 1 have come and gone, and reappeared, over the years; some are now hard to find, while others may come around again if you wait long enough. The No.1s design also readily lends itself to the use of blackpowder ammunition.

The original version of this rifle was the No.1-B Standard; this rifle was chambered for 9 cartridges, but later several more chamberings were added: in 1973, .338 Winchester Magnum; in 1979, .280 Remington; in 1984, 5.56mm NATO; in 1986, .270 and .300 Weatherby Magnum; in 1987, .257 Roberts; in 1992, .218 Bee; in 1993, .22 Hornet, and in 2002, 7.62mm NATO. The No. 1-B has a walnut stock, metalwork of steel and deeply blued, and no iron sights (but drilled and tapped for a scope, and also including a quarter-rib scope mount), and a 26-inch barrel. The butt has a thick rubber pad on it. In 1997, a stainless steel version of this rifle was introduced, the K1-B-BBZ; this version is made in less chamberings, but many of these chamberings are different than the No. 1-B. As with the No. 1-B, the 7.62mm NATO chambering was not available until 2002, and the .204 Ruger chambering in 2004.

The No. 1-A Light Sporter was introduced in 1968; it has a barrel 4 inches shorter and is much lighter. It has a folding leaf rear sight and a high front gold bead sight. The stock is of walnut, with an indented fore-end (similar to the Henry rifles). Unlike most of the No. 1 series, the No. 1-A remained virtually unchanged, with only one variant appearing (the No. 1-AB Light Standard), in two additional chamberings and two chamberings standard for No. 1-As. The No. 1-AB did not sell well and was pulled from the market in 1983; it did not appear again until 2005, this time chambered only for .204 Ruger. In addition, the .204 Ruger chambering was added to the No. 1-A. (Personal Note: I honestly cannot see any difference between the No. 1-A and No. 1-AB, except for the chamberings of the pre-1987 version…) A new (as I write this in late-October 2009) chambering was added – the .300 Ruger Compact Magnum, essentially a super-short Magnum round.

The No. 1-S Medium Sporter was introduced in 1967. This version has a 26-inch barrel for most chamberings, and a laminated walnut stock with a Henry-type indentation in the fore-end. It was introduced in two chamberings, but .45-70 Government was introduced in 1973 (but available only with a 22-inch barrel). 1992 saw a .218 Bee chambering introduced. A stainless steel model, the K1-S-BBZ, came out in 2001, chambered only for .45-70 Government and only with a 22-inch barrel; it is identical to the standard .45-70 No. 1-S for game purposes. By 2007 only the .45-70 chambering and a new chambering, 9.3x74R, were available.

The No. 1-H Tropical Rifle was also introduced in 1968. This rifle is designed for heavy magnum cartridges, and has a 24-inch heavy barrel. The Tropical Rifle has a folding rear leaf sight on a short barrel rib which is also capable of taking a telescopic sight. The Tropical Rifle has a sling, unlike other No. 1s. New chamberings for this version did not appear until 1992, when a .416 Rigby version came out; in 1993, .404 Jeffery and .416 Remington Magnum were also added. (The .404 Jeffery version was removed from the market in 1995.) A stainless steel version of this rifle, the K1-H-BBZ, was introduced in 2000, chambered only for .375 H&H Magnum; it is identical to the .375 version of the Tropical Rifle for game purposes. A .405 Winchester was added in the early 2000s to the standard No. 1-H, and in 2007 the .450/400 Nitro Express, and the .458 Lott chamberings were also added; in addition, the .405 Winchester, .416 Rigby and .458 Lott chamberings were added to the K1-H-BBZ.

1969 saw the introduction of the No. 1-V Special Varminter. This version has a heavy 24-inch barrel and is made primarily for small calibers. Instead of the raised barrel rib for mounting scopes and/or sights, the Special Varminter is drilled and tapped directly for a scope mount, and comes with rings for a scope. It has no iron sights. It was introduced in six chamberings, but in 1974 the .222 Remington chambering was dropped, and from 1991-93, the 6mm Remington chambering was also not produced. From 1993-98, .22 PPC and 6mm PPC chamberings were produced. In 1990, the barrel length for the .220 Swift chambering was changed to 26 inches due to the cartridge’s ballistic characteristics. A stainless steel version of this rifle (the K1-V-BBZ) was added to the line; this version was chambered only in .22-250 Remington, and is identical to the standard Special Varminter in that caliber for game purposes. The two 6mm chamberings and the .22 PPC were stricken in the early 2000s, but the .25-06 chambering was added. The K-1-V-BBZ added the .204 Ruger chambering at about the same time, with an optional 26-inch barrel.

From 1972-86, a simplified version of the No. 1, called the No. 3, was built. The No. 3 had a simplified low-wall mechanism and a shorter 22-inch barrel. This weapon was introduced in two chamberings. In 1974, .45-70 Government was added. In 1980, 5.56mm NATO and .375 Winchester were added. In 1985, .44 Magnum was introduced to the No. 3. The .30-40 Krag chambering was removed in 1979, and by 1985, the No. 3 was available only in .44 Magnum and .45-70 Government.

The No. 1-RSI International appeared in 1983. This is a carbine version with a full-length Mannlicher-type stock and a short 20-inch barrel. It was introduced in three chamberings, but 7mm Mauser was introduced to the range in 1984.

Twilight 2000 Notes: Models of this rifle chambered in 7.62mm NATO do not exist in the Twilight 2000 timeline. In addition, the K1-B-BBZ, K-1S-BBZ, K1-H-BBZ, K1-V-BBZ do not exist.