The 6.53mm (.257) Lazzeroni Scramjet was designed by John Lazzeroni in 1996. They are factory loaded in Tuscon, Arizona and makes these proprietary cartridges for long ranger shooters who are looking to take down game at a range of 500 or more yards distance. They have a cross-member jacket design, bonded front core.
The ballistic performances based off three grain types for the Lazzeroni Scramjet hand loading brass on muzzle velocity based on a 27 inch barrel with a 12 inch twist are 3,952 ft/s (85 gr Nosler BT w/76 gr Alliant Reloader 19), 3,707 ft/s (100 gr Nosler P w/ 73 grain Alliant Reloader 19), and 3,501 ft/s (115 gr Nosler P w/74 gr Dupont IMR-7828). These are considered the maximum recommended loads for hand loaders and further information can be found on the Lazzeroni page for hand loaders to follow.
The 6.53 Lazzeroni Scramjet can also be purchased with factory loads available from a variety of web dealers including the Lazzeroni site. The cartridges are considered some of the best proprietary cartridges available on the commercial market and can be used for shooting varmints, small game, or medium sized game at long range distances.