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Common know. to aim 3" low: 25 yards or more?

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This looks like a really dumb question, but being fairly new to plinking etc, it was not always obvious when shooting at objects about 30-50 feet away.
I've never had any shooting lessons (age 52).

At my first outdoor range, a much more experienced buddy sat and kept the Mosin Nagant 44 on the 'v' in the wooden block and never ONCE hit the 18" target at 50 yards, nor the surrounding rectangular cardboard, even with the bayonet extended.
Yesterday (two days later-still puzzled:confused:), I asked an older gent, former firearms instructor, to give me some basics which any Army Private learns in Basic Tng. (at OTS [Medina Annex] in '78 we fired .38 wadcutters once or twice-nothing else), this time from only 25 yards with the Mosin and Mini 30 using iron sights from the same wooden block.

He saw me consistently aim at either the bulls eye and hit 3-4" higher than two planned aim points, except for one trigger jerk: either at the bull's eye or the middle yellow ring halfway from the bull's eye to the bottom ring.

The gent told me that many iron sights are made for us to line up the rifle's front post right in the rear notch and aim at the bull's eye-If we are about 100 yards/meters away. Apparently many rifles' bullets actually curve a bit upwards as soon as they leave the muzzle.

You can't hurt my feelings, but I've never heard or read this being new, maybe because nobody shoots much less than 100 yards at a range etc. I noticed the Minis shooting high weeks ago, but the Mosins? For the most part it was only my second time at any rifle range, and when young, I could use a .22 and hit a turtle on a log at about 70 feet (seldom went plinking back then). As a new hobby right now, my shooting has been almost always solo down into a rural river with high banks on both sides.
Many 10 year-old country kids know more than I do.:eek:
Maybe I should keep quiet and make it look like I know such basics.
 
Sorry to hijack the thread, but what is the answer to the thought question on the Chuck Hawks trajectory page?

I would think that in both cases (aimed directly up and directly down) the bullet would diverge from the point of aim and never cross it again because gravity is not acting horizontally.

How does this translate to an in between angle, for example a rifle aimed at a 45 degree angle upwards? Do you have to aim low?

Is it the same for a rifle aimed 45 degrees downwards?
 
IO - I suggest You start shooting at short distance and try to do everything right, not looking at a target too much (You said someone has already shown You the fundamentals). At close range you'll almost sure to hit a target, no matter what You do. Assuming You have a decent rifle after short practice You'll start to hit at one spot, meaning You're doing Your part of the job. Than You should check if the point where the bullets impact the target is the one You are aiming for, and if not - try and regulate the sights. When You will set sights to hit at a point of aim at a certain distance ("zero" the sights) You'll hit lower at greater distances.

Vermont - A bulet shot vertically will intersect with line of aim and continue to go "higher". Given adequately long distance to travel the one shot down will go vertically down, the one shot up will travel an arch and fall down behind shooter's back.

A rifle aimed up or down an angle will hit higher than zeroed.
 
Roger that and thanks:

In about three hours I meeting with a guy who is selling me his nice unused SKS.
That will make mine an interesting and fun rifle family (only had an ancient .22 until last October).
 
Usually if you are zero'd at 100 yards, you will be very close at 25, if anything, you would be low at 25, not high. At about 35 yards, the point of impact should be the same as 100 yards.

Some rifles are going to shoot low at shorter ranges if they are zeroed at 100 yrds due to the height of their sights above the bore- at 10 yards a AR-15 that's zeroed at 100 will shoot low.
 
Vermont - concerning the thought problem: He didn't put enough thought into formulating the question. ;)

Anyway, if by "aiming straight up and down", he means straight up/down when using the sights, then the trajectory when firing up will be a very steep but skewed parabola in the direction of the sights. It doesn't matter how the rifle is oriented, the bullet will always travel toward the sight line, cross it and continue up until its velocity is zero (slope = 0) at which point it will continue along the parabolic until it comes back to earth. I termed the parabola "skewed" because the velocity going up will be much higher than coming down. (Effects of wind, baro. pressure, earth rotation all ignored.)

When fired down, I guess from a balloon platform for example, the bullet's trajectory will be a very shallow parabola again oriented toward the sight/sight line. Although, intuitively, I don't think the trajectory will trace a complete parabola such as the fired-up bullet will. (That is the focus will not be equidistant from the end points.) Again, as with the fired-up bullet, the parabola will not be perfect due to the velocity differential at the beginning and end points.

How does this translate to an in between angle, for example a rifle aimed at a 45 degree angle upwards? Do you have to aim low?
Yes, you always need to aim a little lower than you would in a horizontal situation if the rifle is sighted in that way. That's true when firing up or down. The simple explanation is that the bullet is under the influence of gravity for a shorter period of time when fired at an acute angle even though the distance to the target might be the same. There are tables you can use to determine how to adjust your sights for uphill or downhill shooting.
 
Mal: If you're going to be so nitpicky, I'll be a little nitpicky. :)

The bullet will not have a zero velocity at the apex of its travel.

It will have zero velocity in the up direction.

It will still have a nonzero velocity in the horizontal direction.
 
Nit picking right backatcha! You're thinking is correct, but your terms are wrong. Velocity is a vector quantity, the velocity (in the y direction) of the bullet will indeed be zero when the slope is zero (at the apex). IOW, the velocity I'm thinking of is the velocity with respect to the earth.

Now the speed of the bullet will not be zero as it makes the turn, but that's immaterial. I was using velocity to indicate where the bullet ceased its upward travel and started down. I, insufficiently perhaps, indicated that the bullet is still moving with the statement, "at which point it will continue along the parabolic". If the bullet actually stopped moving, it would then fall in a straight line back to earth. That would be against all natural laws! ;)
 
Whew, glad I went into Forestry. Biological mathmantics and statistics, biometrics, as well as the silvicultural elements in all the worlds various ecosystems seems far more straight-forward...

Ash
 
Ech, guys...

Though I'm not US citizen and have a little truble with the language I was trying to be simple and easy to understand by the author of the thread that wrote he was new to guns and wanted a straightforward answer to basic question.

And suddenly there Ya go with explanations of the "what if" variations of variants of different possible situations. :) I wonder if he is now much more knowledgeable than before...
 
Hey now, you just said velocity, not "velocity in the up direction" or "the z-component of velocity." ;)
 
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