Point of impact and point of aim.

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I've been shooting relatively short ranges both with a pistol and a rifle. I've not really had cause to adjust much, but I do want to be able to shoot the pistol to 50 yards and my rifle a bit further. I'm curious about trajectory calculations, all that I can find on the net seem to be programs which calculate for you. But, it would be nice to have a formula or another method even a chart I could refer back to when adjusting my aim. With my rifle it would appear that she is fairly accurate at the 150m range judging from my 100 yard workout. My short distance is a bit high and at times a bit low. The low I know is a trigger slapping or jerking issue I have after I start getting tired. The high I believe is a point of aim and point of impact issue. Any reference links would be appreciated. My current calibers are 9mm Luger usually 124gr, .32ACP at 73gr and 7.62x54R at 182gr.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Point of impact and point of aim.

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I ignore the differences between POI and POA in hand guns.

Now, rifles, I've done some work. It turns out that each rifle is a bit different from others like it, so rounds have to fly downrange and data collected.

A term to research about: Maximum Point Blank Range (MPBR). If your rifle is right on left to right, that's where to start. At 25 yards the bullet is still on its way up and will cross the line of aim once on the way up and again on the way down. Learning where these two points are with your rifle is the beginning.

Let's take a Mosin to start with. If you zero it at 175 yards, you end up with a three inch tube that's 175 yards long where anywhere along that line you will hit within a three inch circle. If you increase the zero to 200 yards, things change between 175 and 200 quite a bit.

My goal is to know the MPBR of each rifle, to have loads for 150 and 180 gr bullets, and to have a chart to refer to.

Best of luck.

CDFingers
Crazy cat peekin' through a lace bandana
like a one-eyed Cheshire, like a diamond-eyed Jack

Re: Point of impact and point of aim.

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Thanks CDFingers! That's what I want to work on! Up to this point I have not concentrated on this aspect; but, while at the range my cousin started looking at the box for a chart or table and was surprised it wasn't included. We or actually he did his own test by first shooting at the 50 yard and then the 100 yard range. I'm looking forward to fun range trips!
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Point of impact and point of aim.

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CDFingers wrote:This is a neat link, and the site itself is filled with goodies. You'll find trajectory tables for several different Mosins and many, many brands of ammo.

http://7.62x54r.net/MosinID/MosinAmmo.htm

CDFingers
That's always a great link! :love: I did look at it before; but didn't know how comparible those graphs were with the M39 and the PPU FMJ BT 182gr we were using. The Prvi Partizan it has listed is a 180gr SP and I don't have any experience or knowledge to know how different they are from each other. But, now that I look at it again and recall your (CDFingers) previous post the trajectory for 200m looks fairly similar in all ammo and rifles cited. I'll make a few range cards and also start a file on my phone before my next range trip. Unfortunately my next time out with her will have to be in November after the annual meeting in October! :weep:
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Point of impact and point of aim.

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Today I did some work at 200 meters with the Mosin Camo target rifle with 150gr milsurp. My goal was to get it printing center at 200m, which I got.

So: when you check through those graphs, you can see that it will hit about an inch high at 175m, and about 3 1/2 inches high at 100m. Once I know the range, I can hold over or under. But even if I hold center, what ever I shoot will know it's been shot--for a few seconds at least.

CDFingers
Crazy cat peekin' through a lace bandana
like a one-eyed Cheshire, like a diamond-eyed Jack

Re: Point of impact and point of aim.

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CDFingers wrote:Today I did some work at 200 meters with the Mosin Camo target rifle with 150gr milsurp. My goal was to get it printing center at 200m, which I got.

So: when you check through those graphs, you can see that it will hit about an inch high at 175m, and about 3 1/2 inches high at 100m. Once I know the range, I can hold over or under. But even if I hold center, what ever I shoot will know it's been shot--for a few seconds at least.

CDFingers
CDFingers are you shooting with any support or just hand support. I need to at lest rest the rifle on a bag or similar support. I'll have to try supporting just with my elbow, but haven't tried that yet.
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Point of impact and point of aim.

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CDFingers wrote:Oops: should've said. I was shooting prone. I have this old blue back packing sleeping pad I use for prone shooting.

CDFingers
I'll have try that! I'll look for a range that allows it. The one I've gone to requires one to shoot from a bench and it only goes to a 100 yards. Last time I've shot anything prone was a 22 in 1973!
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"Resistance is futile. You will be assimilated!" Loquacious of many. Texas Chapter Chief Cat Herder.

Re: Point of impact and point of aim.

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sikacz wrote: CDFingers are you shooting with any support or just hand support. I need to at lest rest the rifle on a bag or similar support. I'll have to try supporting just with my elbow, but haven't tried that yet.
Try a double-point sling like the one here:

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Much comfier than a single-point lk emost target guys use, and can be used to (gasp!) carry the rifle, too. Just make sure the aft end is forward of the mag well, and that one end has a swivel for a half-turn where it goes over the forearm. :)

A set of elbow-pads doesn't hurt, either.
"We have met the enemy and he is us." Pogo.
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Re: Point of impact and point of aim.

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SailDesign wrote:
A set of elbow-pads doesn't hurt, either.
Yes: I used the flat pillow I bring to bench shoot, and I used it for elbow pads on top the sleeping pad.

Lately I'm on a "field positions" kick.

Here's fun to be had learning about each rifle: Make sure it's sighted. Then you put a target at 25m and aim at the center.
Shoot a three shot group aimed at center; circle and mark it. Then move it to 50m, three aimed at center; circle and mark it. 75m, three; circle and mark it. 100m, three; circle and mark it, then, finally 125m with three; circle and mark it. You'll have your two points and how your bullet flies to 125m. Always aim at the center so you can see how the trajectory moves.
I've done this with a few so far. It's fun, but when the range is busy is not the time. Early morning on a weekday is the best.

CDFingers
Crazy cat peekin' through a lace bandana
like a one-eyed Cheshire, like a diamond-eyed Jack

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