 With the 8mm Remington Magnum as the parent case wildcatters have created 6.35 mm (0.257 in) (.257 STW), 6.5 mm (0.264 in) (6.5 mm STW), .30 caliber (.30–8mm Remington Magnum, .300 Jarrett), 8 mm caliber (8 mm Jarrett), .338 caliber (.338 Jarrett), 0.358 in caliber (.358 STA) and 9.53 mm (0.375 in) (.375 JRS [John R. Sundra]) variants.Another brainchild of Layne Simpson, the .358 STA is an 8mm Remington Magnum case necked up to accept .358 Caliber bullets with the shoulder angle changed from 25 degrees to 35 degrees and body taper removed to maximize powder capacity.Able to propel a 300 grain bullet at over 2700 feet per second for 4,900 ft./lbs.