Fastest Factory Cartridge?

[Gordon]

Well my .224 Clark (22-257 roberts improved)28" barrel isn't factory and with a 1 in 8" twist it is made for 75 grain bullets at 3600+fps BUT I have loaded 40 grain ones at 4440 fps at 15'.

 

[Jake1996]

The 220 swift federal for the past 2 years has made a 40 grain nosler at 4250 fps

 

[BrocLuno]

I thought maybe Lazzeroni had passed the Swift, but looks like NO. I guess I'd call a Lazzeroni ScramJet a "factory" round. But at $99 a box - it ain't cheap. Still, an 85 grain bullet at 4000 FPS is pretty impressive

 

[Jake1996]

You can load the swift with a 50 grain bullet to 4400 fps