The newer steels are better than they used to be Ray, and it seems like they stay a bit more accurate a bit longer.
But yes, that much powder in that small a hole is going to be hard on the barrel.
The .220 Swift is a bit harder on barrels than say a 22-250, but if you dont get it so hot that you could cook an egg, it will last a long time. Keep em cool and clean and most people will never shoot out a barrel.
I bet I will see upwards of 1000-1500 hundred rounds out of this barrel before it gets too lousy.
That seems like a lot but I am at 250 already, and I am still working up loads!