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Chuckwagonsam
October 18, 2010, 07:39 PM
Hi to All,
First post. I'm looking for advice on how to adjust the front iron sight on my 45-70 sharps. It hits 6" low at 25 yds. and won't hit paper at 100 unless I hold a foot or so high. I hold the front sight level with the rear and put target on top of sight.

arcticap
October 19, 2010, 10:22 PM
The height of the front needs to be lowered to raise the point of impact. How much it needs to be lowered is based on a formula. But you do need to decide the distance that you want to have the sights zeroed in at because they may not be regulated the same for every distance or load.

The formula for front sight adjustment or replacement is:

Record:
error on target in inches
distance to target in inches
sight radius in inches.
divide error on target by distance to target,
multiply by sight radius.

If rear sight is adjustable, adjust to middle of it's adjustment limits to allow a range of adjustment up or down after replacing or modifying front sight.

For example, if the sight radius on a pistol is 10 inches:

error on target= 12" low.
distance to target is 900".
sight radius is 10".
12" divided by 900" = 0.01333 x 10" = 0.133".

The front sight has to be lowered by 0.133 inches or a bit more than 1/8 of an inch (.125)

Chuckwagonsam
October 20, 2010, 08:57 AM
WOW! I knew I shouldn't have slept through math class. Thanks