Well...the problem has been solved!
It appears that the problem was threefold: 1) Bad brass, 2) A finicky rifle, 3)Seating depth (possibly)
My buddy loaded a whole bunch of different loads and bullet/case/powder combinations to see what would work. I also bought 100 pieces of new Winchester brass and gave up on the inconsistent and problem ridden "once fired" brass I bought from someone else on Sniper's Hide. (No names will be mentioned here...)
After a lot of work, we found that the following load(s) consistenly shot 1/2" or 3/4" at 100 yards:
- 180 grain Nosler Ballistic Tip and 75 grains of Hodgon H4831SC
- 180 grain Sierra Match Kings and 75 grains of Hodgon H4831SC
(We seated the bullets slightly deeper than the first loads pictured above.)
These were tested with success in my new Winchester brass. For whatever reason, my rifle hates Swift Sciroccos, Nosler Accubonds, Ballistic Silver Tips, and Alliant Reloder 22 powder. Go figure.
We're going to load up 100 rounds of the Ballistic Tips, check the load with the chronograph, and then confirm the Exbal drop tables. After that, I'll practice on steel at various ranges from the major positions.
I sincerely appreciate all of the replies, private messages, and emails that were offered. Your input has been invaluable.
Some lessons learned on my part:
1) Don't ever buy second hand brass again, no matter what.
2) Don't give up on your rifle until you have tried plenty of combos; even if the popular loads/bullets don't work, that doesn't mean that another one won't
3) Don't get hung up on trying to force a particular bullet to work for you. Just because it's supposed to the be a bad-ass super bullet doesn't mean it will shoot worth a damn for YOU. Be open to trying something else.
4) Prep brass
5) Study more about reloading and case development
Words cannot describe the relief that I feel in knowing that my rifle is not a lemon and that I now have a load that has been repeatedly proven to be accurate out of this rifle. No elk within range will be safe now!