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How Much Off Target?
Posted: Sun Mar 26, 2017 3:14 pm
by G26ster
I know there's a formula for measuring horizontal distance at a known range, but I forgot the formula from my forward observer days long long ago.
Hypothetical:
A shooter has his firearm zero'd at POA (target center dot). With his sights lined up at POA, he moves the barrel 1/8" right or left on trigger pull. How much off the center dot would the round be at 7 yards (252")? Any know how to calculate?
Re: How Much Off Target?
Posted: Sun Mar 26, 2017 3:38 pm
by hovercat
Is the pivot point at the nose of the bullet?
What is the distance from there to the muzzle?
Re: How Much Off Target?
Posted: Sun Mar 26, 2017 3:43 pm
by hovercat
Assuming yes and 4 inches, the bullet would move 3 one eigth per foot, x7. 21/8 or 2 5/8 inches.
This ignores that the bullet is actually traveling in a spiral as it leaves the barrel.
.
Re: How Much Off Target?
Posted: Sun Mar 26, 2017 3:56 pm
by SlowJohnny
I got that your shot would be off 7.88" which considers that you have a 4" barrel and that your barrel pulled 0.125" (or 1.79 degrees).
Re: How Much Off Target?
Posted: Sun Mar 26, 2017 4:52 pm
by G26ster
Thanks guys.
Hovercat: 3 one eigth per foot x 21 feet = 63/8 or just about 8 inches - no?
Re: How Much Off Target?
Posted: Sun Mar 26, 2017 5:45 pm
by C-dub
What language are y'all talking?
Re: How Much Off Target?
Posted: Mon Mar 27, 2017 4:20 pm
by RossA
I stopped doing math word questions when I got out of high school.
Even then I mostly failed them.
Re: How Much Off Target?
Posted: Mon Mar 27, 2017 4:36 pm
by hovercat
G26ster wrote:Thanks guys.
Hovercat: 3 one eigth per foot x 21 feet = 63/8 or just about 8 inches - no?
My bad, mixed up feet and yards. I feel foolish, glad I did not do that at work on the construction site. Yes, about 8".