At 100 yards each change in sight height will change it by 1.87"
So if your rifle has a 0.0 front sight and you put a 0.015 blade in it will move the point of impact by 1.87" There were originally 8 different sight heights (if i remember correctly) for either the No1 & No3 (P14), or the No4 & No5. The No1 & No3 are different than the No4 & No5 so make sure you get the right type.
If you want to zero at 100 and are shooting 6 inches high at 100yards
6/1.87=3.20 Therefore you need to increase your front sight height three sizes.
However, and I hope that I don't confuse people here, If you want your No4 to have a military zero of 300 yards, it will shoot high at 100.
To give your No4 a military zero (300 yards) using a 100 yard range, proceed as follows.
1/ First off, get a bayonet.
2/ Mount said bayonet.
3/ Shoot a few rounds, and see where the impact the target.
4/ Now here is the important part. They should be impacting 8.5" above the point of aim. If they were to continue downrange to a target 300 yards away they would hit the point of aim. (At least that's the theory that Shoot To Live has taught me)
5/ Adjust sights as needed, as described above.
Tell you what, when my sets of sights arrive, hopefully soon (fingers crossed), I'll do a step by step pictorial of both zero's. (I've got 2 No4's, I want one zeroed at 100 and one to have the military zero)
