Re: 6.5-284 erosion
THat depends on how hot you let it get during firing, the metalurgy of the barrel steel, the amount of powder you are using, and the makeup of the powder itself you are using. Nitrocellulose based single base powders are easier on barrels than nitroglycerin/nitrocellulose double based powders (ball powders are double based but produce lower flame temps because of the retardant coatings used to slow the quickness). The triple base nitroglycerin/acetone/sulfuric acid powders like the "5" series VV powders are super hot and have extra long peak pressure curves that can damage a throat very quickly if abused.
That being said, after only 418 rounds, I would say you are showing slightly higher than normal erosion supposing a single based powder.
My 6.5-.284 hasn't lost much after 1100 rounds using nothing but Alliant RL 22 (which is a double base I believe or at least it used to be when Hercules owned it). The throat has stayed put pretty well, but cracking and the lakebed look has set in. [img]/ubbthreads/images/graemlins/frown.gif[/img]
If it's not far, it's boring.