Group

Group may refer to:

Groups of people

In science and technology

In mathematics

In chemistry

In computing and the internet

Other uses in science and technology

Other uses

Shot grouping

In shooting, a shot grouping, or simply grouping, is the placement of multiple shots on a target, the shots taken in one shooting session. The closeness of the grouping, the nearness of all the shots to each other, is a measure of the accuracy of a weapon, and a measure of the shooter's consistency and skill.

Uses of the term

For firearms that shoot one round at a time, a shot grouping can be used to measure the accuracy of the system comprised out of weapon as well as the precision and uniformity of the ammunition by fixing the weapon into position on a test mount, and aiming it at a target. Multiple shots using rounds from same type and batch are fired to observe how the weapon groups the shots. If a person holds the weapon and shoots it, the grouping measures the combination of the person's skill and the weapon's accuracy.

In shotgun shooting, the grouping is also called the pattern. The pattern is the spread of shot from a single shotgun shell, measured as the smallest circle containing all the shots on the target. The barrel of a shotgun is designed to deliver a wide or narrow grouping, depending on the expected use. Shooting at close range indicates a cylinder bore barrel to deliver a wide grouping, while for hunting at longer distances such as 50 yards or meters, a choke is recommended for a tighter grouping.

Stratigraphic unit

A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it.

Units must be mappable and distinct from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%".

Lithostratigraphic units

Sequences of sedimentary and volcanic rocks are subdivided on the basis of their lithology. Going from smaller to larger in scale, the main units recognised are Bed, Member, Formation, Group and Supergroup.

Bed

A bed is a lithologically distinct layer within a member or formation and is the smallest recognisable stratigraphic unit. These are not normally named, but may be in the case of a marker horizon.

Member

A member is a named lithologically distinct part of a formation. Not all formations are subdivided in this way and even where they are recognized, they may only form part of the formation.

Hip hop music

Hip hop music, also called hip-hop or rap music, is a music genre formed in the United States in the 1970s that consists of a stylized rhythmic music that commonly accompanies rapping, a rhythmic and rhyming speech that is chanted. It developed as part of hip hop culture, a subculture defined by four key stylistic elements: MCing/rapping, DJing/scratching, break dancing, and graffiti writing. Other elements include sampling (or synthesis), and beatboxing.

While often used to refer to rapping, "hip hop" more properly denotes the practice of the entire subculture. The term hip hop music is sometimes used synonymously with the term rap music, though rapping is not a required component of hip hop music; the genre may also incorporate other elements of hip hop culture, including DJing, turntablism, and scratching, beatboxing, and instrumental tracks.

RAP99

The RAM P99 is a paintball marker manufactured by Chinese company Qian Wei and distributed in the United States by Umarex USA under the "Real Action Markers" brand. It is distributed in Europe by Umarex, Germany. The RAM P99 is made under license and designed to replicate the Walther P99.

Operation

Powered by a 12g disposable CO₂ cartridge or re-fillable internal air system, it features a blowback design and 9 shot capacity magazine using .43 caliber paintballs or rubberballs. The trigger is double-action (DA/SA). First versions did not have a conventional on/off safety. Current versions now have a manual trigger-lock safety. The marker is cocked by working the slide and there is also a functional de-cocker. It differs from the RAP4/5 system as it does not use (and therefore) eject shell casings. Muzzle velocity is adjustable between 200 ft/s and 300 ft/s. For .43 cal paintball - 0.029 oz it is about 3.4371 J (at 300 ft/s).

Use

The RAM P99 looks, feels and shoots with great accuracy just like the Walther P99 firearm making it ideal for law enforcement and military training, especially close quarter battles and room clearings. The RAM P99 is also used for virtual reality paintball play.