http://www.iforgeiron.com/topic/14588-jack-hammer-bits/
Grant Sarver said.....
Having been a manufacturer of paving breaker bits, I can tell you that no one uses S-7 or any real tool steel ( at least not in 1", 1-1/8, 1-1/4). I've had just about every one spectrographed. B&L is a modified 1045, Vulcan used to use 1078 but now uses 15B30, Pioneer/DelSteel is 1078 or 9260 for their "alloy" bits. Apex (my old brand) are 8630. These things sell new (at full discount) for about what tool steel costs per pound. Everybody is looking for the cheapest thing that will do the job. People expect these bits to be really great stuff, perception trumps reality every time.
BTW: "Paving breaker" bits are solid, "jackhammer" bits have a hole down the center.