Most used alloy for 223 bullets

pat i.   What you can get in the same cartridge with top jacketed loads, but there's a but.  Such low velocity rounds such as 30-30 or such don't count. Talking like 30-06, 7x57, 5.56, you know.  

Shooting for jacketed bullet velocities with a lead bullet is a pipe dream and something not encountered very often. I chambered up a barrel in 30x47 and used a 160 grain LBT bullet at 2550 fps. It was not worth the effort. I know you said you need high velocity to burn out a throat with Lino but it seems to be the gold standard with guys shooting around around 2100 fps in the matches. If it's as abrasive as you say the throat would be worn out going 2100 or 2800 fps. I've looked at barrels with high round count and except for fire cracking they still shot great. If the things were being moved forward from the wear from antimony I'd think the wear would be perpendicular to the bore but every one the cracking was across the lands which leads me to believe it had a lot more to do with heat than antimony. BUT as I said in my previous post I think a shot out throat is an easy thing to blame for a rough spell at the range, that along with a scope going bad.

Okay my friend pat, let's get this figured out.  First your 30x47 cartridge with a 160 grain bullet to 2550 fps is very well into the realms I speak of, of HV with a cast alloy. I also had told that it's difficult to do, surely not easy.  I also explained that the heat cracking (those words alone HEAT CRACKING) tells you that I said it was indeed the heat, added to by bullet friction, that indeed cause the cracking. You can't cause any kind of cracking with any kind of alloy, you know that. That fellow that I mentioned that speedingly wore his throat by shooting Linotype at high velocity MEASURED the wear. So for him it's not an imagined thing, it was actually physical wear of his throat. He was pissed to say the least. Because I wasn't a friend of his my telling him wasn't believed.  Well he found out.