.20 BR

20BR is one of the many 20 caliber rifle cartridges known as wildcats (not commercially available). It is basically a .22 BR Remington case necked down to accept a .204" diameter bullet maintaining the same shoulder angle and overall length. It was primarily created to combine large powder capacity with a short efficient case design thereby giving superior performance to other 20 caliber wildcat cartridges in common use. Combining the ability to propel a 40 grain bullet above 4000fps and the inherent accuracy of the BR case design, the 20BR quickly became the preferred flavour of many varmint hunters and target shooters alike.

Other advantages of this cartridge include; its ability to suit any rifle action which has the 308 Winchester sized bolt facel; its short length enables action makers to utilise shorter ports to increase rigidity; and cases are easily formed and loaded.

Some drawbacks of this cartridge are that it's not commercially available; is considered overbore (a barrel burner) and therefore not economically viable when compared to less aggressive 20 wildcat chamberings.

20 caliber wildcats based on the 6.8mm SPC and 22 PPC present a middleground between the 20 BR and the more common 20 Tactical and commercially produced 204 Ruger.