When target shooting, I usually use the most accurate load in the rifle, In the .69 though, that would mean a LOT more powder than is comfortable shooting a number of shots, thus
for the closer ranges, out to 100yards, I was using 82 to 85gr. of 2F GOEX. Once I ran out of GOEX and had to switch to Schuetzen (Wano for Germany) I had to find a "new" accuracy load.
The current 50 yard October Postal match found me experimenting (again) & shooting my best group with 113gr. 2F Schuetzen. I did not know what the measure "threw" until getting home and weighing it.
The marking of the measure's rod, indicated something over 100, maybe 105. This was not a difficult load to shoot as you can see by the group of 4 or 5. As to grouping, this rifle has always shot water based lubes and greases to the same point of impact. Most guns do not, nor do they shoot the same size group with water compared to grease or oils.
Back in the 70's when I started this game, I learned that "loose" ball and patch loads shot best with light charges of powder and when more powder was used, the accuracy went away due to blow-by burning through and burning up the patches due to higher pressures than what the lighter loads gave. Thus, lighter loads were more accurate. As I learned to smooth the crown so I could use denim in .022" thickness and a ball a mere .005" under the bore size, I was able to obtain even better accuracy than was possible before with the looser loads & increasing the powder charge tightened groups further. In all my rifles, I was enjoying much improved accuracy. The 3 .58's I had at the time were all giving 5 shot groups at 100yards
in the realm of 2" and even smaller. The commercial Italian Zouave, .58 Underhammer H&R along with the .58 Hawken Taylor built me. These guns shot their best with 120gr. 2F in the H&R and Zouave and 140gr. 2f in the Hawken with the Bill Large barrel.
All of these rifles would barely hit the page with any load, if I used the earlier looser loads of the early 1970's. After I found out how to load the tighter loads, I found better accuracy with more powder, something the loose loads would not permit. Not sure I have explained this well enough, but there it is. Accuracy load development begins at 50yards, imho.