Author Topic: Proper target size (Read 521 times)

Jim B. · « **on:** June 18, 2004, 03:16:31 AM »

As I get ready for another range session with my 209x50 (technically a .22 Hornet x 50) I recalled a problem from my last session and was hoping someone could help me. The fiber optic front sight on the Encore is nice and visible but it is large - I found it completely obscured the bull of the largest target I brought. For the purposes of sighting in, it would be nice to have a target ring large enough to be able to see some "white space" all the way around the front bead at 100 yds. I remember seeing a formula years ago for calculating the area subtended by a rifle bead at any given range but have lost it. Can anyone enlighten me as to the correct calculation?
Thanks, Jim

AndyHass · « **Reply #1 on:** June 18, 2004, 06:19:30 AM »

So if I understand you correctly, you sight the gun in so the bullet will impact the target in the center of the circle formed by the front fiber optic sight? If I am understanding this correctly, you are sighting the gun in to impact a spot that your sights are obscuring. I'd sight it in so the bullet impacts the spot at the top center curvature of the front sight...That way you can see the spot you are aiming for and don't have to worry about target size...as long as it's big enough to hit! :grin:
Unless I am just not understanding you correctly.

SURVEYOR · « **Reply #2 on:** June 18, 2004, 06:38:58 AM »

The Old 6 o'clock or improved 6 o'clock hold!

Jim B. · « **Reply #3 on:** June 18, 2004, 07:06:26 AM »

I have used the 6 o'clock hold for target shooting but have not had good luck with that as a sight picture for hunting with open sights. With a blade front sight, I do set the sights up so the bullet impacts right at the top-center of the blade. With a bead (or fiber optic dot in this case) I have always found it natural to put the dot where I want the bullet to go - perhaps I need to change my ways! What sight picture do you use with a bead front sight for hunting?

Anyway, the equation I am looking for is a trignometry problem - I think I can solve it if I put my mind to it. I just thought someone might know it offhand.

Jim

Roger_Dailey · « **Reply #4 on:** June 18, 2004, 12:23:51 PM »

Quote from: Jim B.

For the purposes of sighting in, it would be nice to have a target ring large enough to be able to see some "white space" all the way around the front bead at 100 yds. I remember seeing a formula years ago for calculating the area subtended by a rifle bead at any given range but have lost it. Can anyone enlighten me as to the correct calculation?
Thanks, Jim

I believe a fairly simple ratio calculation will get you in the ballpark. Measure 3 things; A) distance from your eye to the target B) distance from your eye to the bead C) diameter of the bead (all measurements in the same units). Divide the distance to the target with the distance to the bead. Use that answer to multiply the diameter of the bead. The second calculation will approximate the area covered by the bead at the target distance. For example: A) Eye to target is 3600 inches B) Eye to bead is 36 inches C) Bead diameter is 1/8 inch or .125 of an inch. A divided by B = 100. 100 times C (.125) = 12.5 inches of target covered with the bead. For your purpose, the eye to bead distance can be off a couple of inches without causing problems.

AndyHass · « **Reply #5 on:** June 20, 2004, 06:28:44 AM »

If it works for you, it works for you and go with it. But I'd personally not hunt with a sight picture like that, as it would require obscuring the target I am aiming at. I love globe front sights, because the curvature of the front globe allows very precise aiming using the very top point of the globe...much better than a flat blade.

edmehlig · « **Reply #6 on:** June 22, 2004, 01:24:07 AM »

I agree with Surveyor, use the 6 O'clock hold and have all your bullets hit at 6 o'clock. It what the Marines taught me in PI. "Point of Aim, Point of Impact". It worked for me back then and continues to work for me now. Think about it, you use the same principle with a scope, why not use the same thought process with Iron sights? So your bullets hits the target at 6 O'clock who cares as long as that is what you were aiming at. Why sight in your rifle to hit X number of inches high to hit dead center for hunting??? If you aim at a deer, you pick out the spot you want to hit and aim for it. You don't think of aim here so my bullet hits up there.

Anyway, just my 2 cents.

Ed