Letter O Firearms Glossary

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Obturation

The process of a bullet expanding under pressure to fit the bore of the firearm, or a cartridge case expanding under pressure to seal the chamber.

OFF

Oregon Firearms Federation. OFF is a Pro-Gun rights group based in Oregon and was founded in 1998.

Off Hand

To shoot while standing and without bracing against anything. Sometimes it can also mean to shoot with your non-dominant hand.

Ogive

A type of curve represented by the curved section of a bullet between its bearing surface and its tip.

Open Bolt

A type of firearm in which the action is in the open position and the chamber empty prior to firing. When the trigger is pressed the bolt moves forward, chambering a cartridge and firing it and returning to the open position. When firing is stopped the bolt remains open and the chamber empty.

Open Frame

Refers to a revolver frame that has no top-strap over the cylinder.

Open Sights

A common type of iron sights in which the rear sight is an open-topped U or a V or a square-notch shape and with a blade type front sight, in contrast to the closed circle commonly found in aperture sights.

Open Tip Match

A rifle projectile made with the tip of the bullet open as a means of increasing accuracy as compared to standard military bullets that are made with a closed tip and an open base. The are not designed to expand like a hollow point bullet but may fragment.

Optical Sight

Usually a telescopic firearm sight.

Oregunian

A person living in the State of Oregon that is a firm supporter of the Second Amendment (plus the other nine Bill of Rights amendments) and generally will also be a firearms enthusiast.

In other words "A Gun Loving Red Blooded American that Hails from The State of Oregon"

OTM

Abbreviation for Open Tip Match.

Out of Battery

A semi-automatic is said to be out of battery when the slide fails to come all the way forward again after the gun has fired. This condition can be created by a misfeed, a dirty gun, weak springs, the shooter's thumbs brushing against the slide, riding the slide, or any of several other causes.

Over Travel

If the trigger is able to continue moving to the rear after the shot has fired, the trigger is said to over-travel.

Over-Under

Can also be spelled Over/Under, OverUnder or Over and Under. A firearm (most commonly a shotgun) with two barrels that are vertically aligned with each other, one on top of the other.

Overbore Ammunition

Small caliber bullets being used in large cases. E.g. .22 bullet in a .45 acp case.

Overbore Capacity

Is that combination of caliber, barrel length, bullet weight, and case volume which does not allow the complete burning of the charge of ballistically correct powder within the volume of case and barrel.

Overshoot

A term used in artillery to indicate a projectile impact beyond the designated target.


3 Other Firearms Definitions You Need To Know


Youth Rifle

A short, lightweight rifle. Some are small enough for a young child to easily handle, while others are large enough to perfectly suit teenagers, average-sized adult women, and small-statured adult males.

Pinfire

An early form of complete, self-contained cartridge. It included bullet, powder and ignition primer, all in one package. The primer was located towards the base of the cartridge, but completely internally. The pin, shaped like a little finishing nail, pointed on the inside end and resting on the internal primer, projected radially about a quarter-inch to the outside of the base of the cartridge. When loaded, a pinfire gun showed the tips of the pins exposed through small slots in the tops of the breech faces of the barrels. To fire, hammers fell on the pins, driving them (through the wall of the cartridge) into the internal primer.

Full Stock

A rifle or carbine with a one-piece stock extending to the muzzle. Sometimes called a Mannlicher stock, although such a term is confusing because Mannlicher Schoenauer rifles are built with both full and half stocks. Traditional in Europe for close-range woodland hunting, but not noted for extreme, long-range accuracy.