NAME – Olsen

COUNTRY OF ORIGIN – USA

DATE OF MANUFACTURE – 1941

CALIBER – 11.43×23 mm (.45 ACP)

OVERALL LENGTH – 85.1 cm (33.5 in)

BARREL LENGTH – 34.5 cm (13.5 in)*

BULLET DIAMETER – 11.46 mm (0.451 in)

BULLET WEIGHT – 15 g (230 grain)

MUZZLE VELOCITY – 290 m/s (950 fps)

MUZZLE ENERGY – 625 j (451 ft/lbs)

WEIGHT (EMPTY) – 3.9 kg (8 lbs 9.6 oz)*

WEIGHT (LOADED) – 4.6 kg (10 lbs 2.3 oz)

SIGHTS – Front sight – blade, Rear sight – notch, both mounted on barrel

EFFECTIVE RANGE – 91 meters (100 yds)

OPERATION – Blowback

TYPE OF FIRE – Selective fire, Semi and Full automatic

RATE OF FIRE – 30 rpm (Semi), 40 rpm (Full)

CYCLIC ROF – 1,111 rpm

FEED DEVICE – 20 round box magazine, single column, single feed

FEED DEVICE WEIGHT (EMPTY) – 0.28 kg (10 oz)*

FEED DEVICE WEIGHT (LOADED) – 0.7 kg (1 lb 8.8 oz)*

MANUFACTURER – A.W. Olsen, H.J. Fitzgerald

STATUS – Obsolete

SERVICE – Did not progress past the testing stage

     Very little hard information survives from this experimental weapon. Developed for the early WWII Aberdeen trials, the Olsen was not a well-developed design at the time of its testing. To operate the weapon on full automatic required pressing in a button on the left side of the weapon and holding it in while the trigger is pulled. For semiautomatic fire, the left side button is pushed in and released prior to the trigger being pulled. Recoil was considered very severe and accuracy suffered as a result. The very high cyclic rate of fire also prevented much accuracy with the weapon when fired on full automatic.

* Estimated