.577 Tyrannosaur

577 Tyrannosaur
577 Tyrannosaur
Type	Rifle
Place of origin	United States
Production history
Designed	1993
Specifications
Parent case	New Design
Case type	Rimless, Bottleneck
Bullet diameter	0.585 in (14.9 mm)
Neck diameter	0.6135 in (15.58 mm)
Shoulder diameter	0.673 in (17.1 mm)
Base diameter	0.688 in (17.5 mm)
Rim diameter	0.688 in (17.5 mm)
Rim thickness	0.063 in (1.6 mm)
Case length	2.990 in (75.9 mm)
Overall length	3.710 in (94.2 mm)
Rifling twist	1 in 12 in (305 mm)
Primer type	Large Rifle Magnum
Maximum pressure	65,000 psi (450 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 750 gr (49 g) Monolithic Solid 2,480 ft/s (760 m/s) 10,240 ft·lbf (13,880 J)
Test barrel length: 26 in Source(s): A-Square Any Shot You Want

The .577 Tyrannosaur or .577 T-Rex (14.9×76mm) is a very large and extremely powerful rifle cartridge developed by A-Square in 1993 for professional guides who escort clients hunting dangerous game. The cartridge is designed for use in "stopping rifles": A rifle intended to stop the charge of dangerous game. The 577 contains a .585-inch (14.9 mm) diameter 750-grain (49 g) Monolithic Solid Projectile which when fired moves at 2,460 ft/s (750 m/s) producing 10,180 foot-pounds force (13,800 J) of muzzle energy. The production model from A-square is based on their Hannibal rifle.