" Big bore shooters use a six o'clock hold, at long ranges a dead on hold blocks out the bullseye. "
Centershot
I don't understand this sentence - I used to shoot big bore competition (full bore = Engish Designation) - always a centre hold, whether in 'scoped' competition or with 'metalics' (always double apertures).
Are you referring to military shooting with issue sights? Really has no weight with ML's, as you'd have to adjust the sights every single target on our trail. Sighting for dead-on hold, impact on the top of the blade or centre of the bead gives a centre hit on every target out to about 65 yards, with a 25 yard zero. Holding a bit of blade or bead 'proud' for the 80 to 100 yard shots is easily accomplished.
Sight set for 6 o'clock hold on a 5" bull would put the ball 2.5" high at 25 yards will put the ball about 4.53" high at 50yds., 4.9" high at 75 yards and zero'd at 122 yards - not very useful for target shooting nor hunting. There is no point blank range at all.
Same low velocity target-type load (1,500fps) most use, if zero'd at 50 yards would be + 1/4" at 25, 0 at 50, - 1/2" at 60, - 2.5" at 80, and minus 5.7" at 100.
Increase the velocity to 1,800fps and the high, 6 o'clock load, same bull is now zero'd at 147 yards & +2.5 @ 25; + 4.9 @ 50; + 6.2 @ 80: + 5.77" at 100.- again, no point blank.
Same 1,800fps load, if zero'd at 50 is 0 at 25; 0 @ 50; - 1.6 @ 80; - 2.69" at 90 and - 4.0 at 100.
Adjusting sights works with good sights, ie: MOA or 1/3 MOA adjustments on target rifles. These are repeatable, whereas cheap adjustables on ML's lack refinement needed for proper zeros -
Of course, all this is subjective and personal preference.