Russia gunmaker proposes hypersonic sniper gun

Vladislav Lobaev, the founder and chief engineer of Lobaev Arms is researching hypersonic ammunition and with funding could create a precision cartridge that will have a muzzle velocity of 2,000 m/s (about 6,560 fps) which is about mach 5.8.

This gun would use special chemicals to reach the higher speeds.

1930s US tested a mach 8 small gun

Is the 1930s,

Currently, small arms cartridges barely exceed the 4,000 fps threshold. The Cheyenne Tactical M-200 rifle chambered in the Cheyenne Tactical .408 cartridge. A 305 grain projectile has a muzzle velocity of 3,500 feet per second.

The .17 Remington has muzzle velocity of 4145 fps. It is one of the few cartridges where the powder load is often heavier than the bullet weight, the .17 Remington was introduced by Remington in 1971 as a varmint load for their 700-series rifles. While its poor ballistic coefficient limits its effective range to around 440 yards, its flat trajectory, low recoil and minimal noise makes it a fantastic choice for varmints and other small predators. Some factory loads can reach speeds of over 4,400 feet per second, making it the fastest commercially-available rifle cartridge.

The .17 Remington Fireball has 4000 fps. It was created in 2007 as a response to many popular wildcat cartridges, the .17 Remington fireball factory loads drive a 20-grain bullet up to 4,000 feet per second. While its velocity is approaching that of the .17 Remington, it does so with less powder, meaning less barrel fouling and lower heat, which in turn leads to longer barrel life.