Steyr ACR

The Steyr ACR was a prototype flechette-firing assault rifle built for the US Army's Advanced Combat Rifle program of 1989/90. Although the Steyr design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.

Design

The Steyr ACR has some superficial resemblance to the Steyr AUG, although it is rounder and the barrel is covered for almost its entire length, as opposed to the AUG where much of the barrel was exposed. Like the AUG the ACR is a bullpup design with the 24-round magazine located quite close to the buttstock of the gun. The stock was "split" from the magazine forward to a location just below the sights to open for cleaning. An optical sight was included as a standard feature.

The Steyr employed a unique system to cycle through ammunition: instead of driving rounds forward into the chamber and being held in place by a locking bolt, the entire chamber traveled vertically the width of the round. After firing the gases "blew" the chamber vertically downward, where a new round was forced into the chamber from the rear, forcing the old round out an ejection port ahead of the magazine. Springs then raised the chamber back into position where it was locked into a fixed block. The firing pin was fixed above the chamber, entering through a small hole and striking the ring of primer to fire. The chamber was normally held in the "down" position, the trigger releasing it to allow the springs to drive it upward and fire.

ACR

ACR may refer to:

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Acrosin

Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ACR gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellucida.

Function

Acrosin is the major proteinase present in the acrosome of mature spermatozoa. It is a typical serine proteinase with trypsin-like specificity. It is stored in the acrosome in its precursor form, proacrosin. The active enzyme functions in the lysis of the zona pellucida, thus facilitating penetration of the sperm through the innermost glycoprotein layers of the ovum. The mRNA for proacrosin is synthesized only in the postmeiotic stages of spermatogenesis. In humans proacrosin first appears in the haploid spermatids.

References

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External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

USS South Dakota (ACR-9)

The first USS South Dakota (ACR-9/CA-9), also referred to "Armored Cruiser No. 9", and later renamed Huron, was a United States Navy Pennsylvania-class armored cruiser.

South Dakota was laid down on 30 September 1902 by the Union Iron Works, San Francisco, California, she was launched on 21 July 1904; sponsored by Grace Herreid, daughter of Charles N. Herreid, Governor of South Dakota, and commissioned on 27 January 1908, Captain James T. Smith in command.

Design

An act of Congress authorized South Dakota on 7 June 1900. The ship’s hull and machinery cost a contract total of $3,750,000. Her plant consisted of vertical triple expansion engines and 16 Babcock and Wilcox boilers, which powered two propellers. Four funnels, one cage mast, and one military mast provided a distinctive silhouette. One Type J submarine signal receiving set equipped the ship. Capt. Charles E. Fox reported on board as the ship’s General Inspector on 30 August 1907. The cruiser completed her preliminary acceptance on 19 November.

Steyr

Steyr (German pronunciation: [ˈʃtaɪ̯ɐ]) is a statutory city, located in the Austrian federal state of Upper Austria. It is the administrative capital, though not part of Steyr-Land District. Steyr is Austria's 12th most populated town and the 3rd largest town in Upper Austria.

The city has a long history as a manufacturing center and has given its name to several manufacturers headquartered there, such as the former Steyr-Daimler-Puch conglomerate and its successor Steyr Motors.

Geography

The city is situated in the Traunviertel region, with the two rivers Steyr and Enns flowing through it and meeting near the town centre beneath Lamberg Castle and St Michael's Church. This prominent location has made it prone to severe flooding through the centuries until the present, one of the worst cases being recently in August 2002. To the south of the town rises a series of hills that climb in altitude and stretch out to the Upper Austrian Prealps. To the north, the hills roll downward towards the confluence of the Enns with the Danube River, where the town of Enns is situated. In the east, the municipal area borders with Lower Austria.

Steyr (river)

The  Steyr  is a river in Upper Austria. Rising in the Totes Gebirge near Kirchdorf an der Krems, it flows into the Enns River in Steyr at a "Y" position. The city of Steyr uses this "Y" for marketing purposes. Its length is approx. 68 km.

Tributaries

Coordinates: 48°02′N 14°25′E / 48.033°N 14.417°E / 48.033; 14.417

Steyr (disambiguation)

Steyr is a city in Upper Austria.

Steyr may also refer to:

See also