Honest opinion, the barrel is done. It appears as if you have a lot of throat erosion from initial load work until now. Depending on powder used, powder charge, ext it can happen faster than expected. Neck tension, seating depth, and a plethora of other reloading practices could potentially tighten your groups, and save said barrel. If you have chronograph data on your previous well known load for that rifle and you have a drop in velocity with the proven load, it is typically a sign of the barrel is headed on its way to greener pastures.
Recheck Lans measurement, trim brass to factory minimum overall case length, check all brass measurements from back of case to shoulder junction. Recheck actual shoulder bump, most of the time the actual shoulder bump measurement does not happen until after the third firing of brass NOT THE FIRST FIRING as the brass has actually fire formed to the chamber. Most people get too excited about shoulder bump and do not allow the brass to actually fit the chamber before bumping the shoulder back. If your action still closes on brass that has been fired without the spring or follower in gaged on the action the brass has not reached its full growth in the chambering. If your action does not close on fired brass then the case has expanded to the full chamber of the rifle. Afte full length sizing of the brass and properly shoulder bumping the brass back 1-4 thousandth depending on personal preference, will you start to actually true your brass to the chamber. Increasing brass life and giving your self a true shoulder bump. If done to early you will actually never fully fire form your brass to the chamber of your rifle. You will actually be setting the neck shoulder junction back plus or minus 5-7 thousandths, and experience a loss in brass life due to the brass never being full formed to the chamber. (Think of it as always fire forming brass, and never getting it fire formed) Properly seating bullets and finding neck tension all play a vital roll in accuracy. Powder charge, primers ext the check list is long but you learn how to shorten it. Deciding whether or not it was the Indian or the arrow, plays a roll as well. It's a never ending trial and error in trying to perfect what works best in your reloading practices and shooting. Best of luck I'm sure you will get plenty of useful and knowledgeable opinions on the subject. Happy shooting.
