The 7mm Shooting Times Westerner, sometimes refereed to as the 7mm STW began as a wildcat

Wildcat cartridge

A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...

 rifle cartridge developed by Layne Simpson in 1979. It is an 8 mm Remington Magnum

8 mm Remington Magnum

The 8mm Remington Magnum belted rifle cartridge was introduced by Remington Arms Company in 1978 as a new chambering for the model 700 BDL rifle. The 8 mm Remington Magnum's parent case is the .375 H&H Magnum...

 case that has been "necked down" (narrowing the case opening) by 1 mm to accept 7 mm

7 mm caliber

This article lists firearm cartridges which have a bullet in the to caliber range.*Length refers to the cartridge case length.*OAL refers to the overall length of the cartridge....

 (.284 in) bullets. This cartridge is named after the magazine Shooting Times where Layne Simpson is a regular contributor.

Background

The 7mm STW graduated to commercial status when it was officially recognized by SAAMI

Saami

Saami or SAAMI can stand for:*Sami people*Sami languages*Sporting Arms and Ammunition Manufacturers' Institute...

 in 1996.
Remington Arms Company was one of the first large ammunition companies to produce this cartridge in 1997, with others like Federal Cartridge Company, A-Square

A-Square

A-SQUARE COMPANY, LLC is a manufacturer of rifles, ammunition and bullets based in Chamberlain, South Dakota in the United States. The company is one of 19 that are members of the Sporting Arms and Ammunition Manufacturer's Institution. The company's focus is on its firearms for hunting large...

, and Speer

Speer

Speer is a surname.*Albert Speer, chief architect of Nazi Germany*Albert Speer, Jr., a German architect and city planner, son of Albert Speer*Bill Speer, a retired professional ice hockey player...

 also carrying it. All mass-market US riflemakers now offer a selection of production models chambered for the 7mm STW, which has established a reputation as a fine long-range elk and large game rifle.

Performance

Dimensionally and ballistically, there are similarities between the 7mm STW and the 6mm cartridge based on the .375 H&H Magnum

.375 H&H Magnum

The .375 Holland & Holland Magnum is a powerful rifle round and one of the best-known and most popular medium-bore cartridges in the world. The .375 H&H was only the second cartridge ever to feature a belt, now common among magnum rounds. A popular misconception is that the belt is for headspace,...

 case necked down, known as the .244 H&H Magnum

.244 H&H Magnum

The .244 Holland & Holland Magnum cartridge was created in 1955 in Great Britain by deerstalker and rifle-maker David Lloyd of Pipewell Hall, Northamptonshire and Glencassley in Sutherland, Scotland, and is not to be confused with the smaller-cased and much milder 6 mm Remington...

.

See also

• 7mm caliber for other cartridges of this caliber. The A Square Nosler 140 gr Partition allegedly has 2040 ft pounds of energy at 500 yards and 2080 ft pounds in its 160 gr. Nosler. A Square reports the highest energy out to 500 yards of any cartridge of similar weights. The 140 and 160 grain cartridges have very similar trajectories and this can be checked out in Tom Forkers Ammo 3 where A Square also has the least wind drift and best drop figures of all cartridges. The 160 gr. cartridge reportedly drifts only 53 inches with a ten mile and hour 90 degree crosswind at 1000 yds. and the 160 gr. caartridges and drops only 200 inches when zeroed at 200 yds. A Square recommends zeroing its cartridges at 300 yds. where the 140 gr merely drops 7.27 inches a 400 yds. and the 160 drops an mere 10 plus inches.