I think a barrel can be seasoned. I've had a couple that I think were seasoned. Don't know for sure as seasoning was never my intent. I read the advertising concerning 1,000 shots without cleaning and decided to try some WL. I shot it as a patch lube for at least 2, maybe 3 years fulltime as a patch lube. So I had several hundred rounds down the barrel on each rifle I was shooting.
I couldn't really see any difference in my shooting but I started seeing it in my cleaning. It got where my patches were coming out with a ugly, thick, coating of brown stuff tinted green. It just wouldn't clean out using my regular cleaning regimins. For awhile I couldn't figure it out so I started writing down my process'ess, and finally saw the problem. I felt like something had changed but what? It was the lube. The WL was the only major change in my loading. When I clean a barrel I want it clean. I want to run a clean patch down the bore and have it come out clean when the barrel should be clean. I figure this coating is what is referred to as "Seasoning". I wanted it out. But nothing seemed to cut it until I wet a patch with brake cleaner. That got it out. Now my barrel gets clean again.
Thing is I still use WL as the lube in my deer loads. Mainly because if loaded on a fresh charge the WL lubed patch will not cause a rust ring in the chamber. I have tried numerous lubes but for my deer loads WL works best for me. Rifles are funny. My turkey rifle shoots super accurate with Canola oil as a patch lube and I use it because it doesn't cause that rust ring either. I'm not concerned about the WL seasoning in my barrels anymore because I know how to get it out. But if I require max. accuracy from either WL or Canola oil I wipe my barrels after a max. of 3 shots.
So after shooting it so long I would like to know the realistic benefits one can expect from seasoning a barrel.