Varmint Hunting Rifles
Since varmints are generally smaller animals, large, heavy bullets are not needed. A light, fast bullet gives a flat trajectory, making range estimation less vital for accurate shot placement. Smaller bullets also produce less noise that might scare the target animal. .25 caliber (6 mm) and smaller rounds are most often used for specialized varmint rifles, with .22 caliber (5.56 mm) rounds being the most common.
In years past, the .222 Remington and .218 Bee were popular varmint rounds, but newer, higher velocity rounds have rendered them all but obsolete. Calibers such as .223 Remington, .22-250, .220 Swift, and .25-06 are common, though varmint rifles tend to be chambered in a wide variety of cartridges, and wildcat cartridges are quite common (the .22-250 and .25-06 got their start as wildcats). Varmint shooting is one of the few areas where calibers smaller than .22 (5.56 mm) are found; the .17 Remington and various other .17 caliber (4.5 mm) wildcats have a vocal following, and the new .204 Ruger is well suited to varminting, and may be the first in a new line of .20 caliber (5mm) rounds.
Useful Info :

The Marlin 17VS is a rimfire, bolt action varmint rifle. It is chambered for the .17 HMR cartridge and features a 22 inch, heavy contour, stainless steel barrel. The substantial stock is made of gray/black laminated hardwood and incorporates a Monte Carlo comb, full pistol grip and rubber butt pad. The detachable box magazine’s capacity is 7 rounds and the rifle weighs 7 pounds.

The Savage 12BVSS is a centerfire, bolt action varmint rifle. It is available in varmint calibers .223, .22-250, and .243. It comes with a stainless steel, 26 inch, heavy fluted barrel. The heavy stock is made of laminated hardwood. Its receiver is drilled and tapped for scope mounts. The internal magazine’s capacity is 5 rounds. This rifle weighs approximately 9.5 pounds and is 46.75 inches in overall length. It is described as a “short action precision long range rifle with dual pillar bedding”.

The Ruger No. 1V Varminter is a falling block single shot rifle. It is available in calibers .223, .22-250, .220, 6mm, and .25-06. Its polished and blued barreled action is bedded in a checkered, select walnut stock. The heavy contour round barrel is 24 or 26 inches in length, depending on caliber. It is supplied with target scope blocks and Ruger scope rings. The No. 1V weighs about 9 pounds. This is a varmint rifle for the connoisseur hunter.
Like others of their breed, the Savage 12BVSS and Ruger No. 1V are highly accurate long range rifles, designed to get the most out of their high velocity cartridges. They will typically be equipped with high magnification, variable power hunting type scopes or fixed power target type scopes. Either type will probably have some sort of fine crosshair reticle and an adjustable front objective that allows the shooter to correct for parallax at whatever range he or she desires.