After yesterday's shooting, where I couldn't hit the broad side of a barn, I came home and Really cleaned the lock/trigger mechanism on my Bobcat. Went back out today and loaded 80 grains of Pyrodex RS, set the life size deer target at 50 yards, and let three shots fly. The bullet was that 370 Grain Maxi Ball. No problems, but I pulled the last shot very slightly. What would have been a 2" group turned out to be about 3". Only problem I find is that I am about 5" below where I am aiming. I am hoping the bullet is still climbing, and will be a little higher at 75 and 100 yards. I have no more room to raise my Lyman Hunter sights any more. I can't wait for deer season!!
CB, at 100 yards you could be in the neighborhood of 14" low. I assumed 1400 fps MV in estimating that. Pittsburghunter mentioned that you can file down the front sight. I thought it may be helpful to calculate how much you may need to trim the front sight so that it isn't an extraordinary amount of trial and error.
Knowing that your 5 in. low at 50 yards and knowing that being 2 in" high at fifty yards willput you about 1" low at 100 yards (assuming 1410 MV),we wish to raise the incline of the barrel so that you are 7" higher at 50 yards than where you are currently sighted.
Divide 7" by 150 ft. (.046667 in./ft)
This is a rise over run figure.
Determine the run of your sights by measuring the distance between the two sights in inches. Divide this by 12 to convert to feet.
Now multiply this number by the rise over runalteration (.046667) to determine how much of the front sight you need to file away.
Example:
Distance between front sight and rear sight = 18in or 1.5 ft
1.5 * .46667 = .07 in
So,
if the run of the sights is 18", then you need to file away a little over a 1/16" (.0625"). If you file more than is needed, then you can lower the the rear sight. If you shoot a faster MV you will need to lower the rear sight. If you shoot a slower MV then you may need to file the front sight some more.
Good luck with your deer this year.
Happy Hunting, Phil