Sighting In

[Wormie]

Unfortunately, I only have a 10 yard indoor range near me at the moment. There is a match that will require most shots to be at 15 yards. I didn't have any time to reload so I'll be using factory ammunition and I figure I'll sight in my glock 34 using this ammunition before the match. So I was wondering if I had sighted in for 15 yards, where will my bullets impact at 10 yards using 124 gr 1140 fps ammo? I'll try to compensate that amount when I sight in at the 10 yard range.

[nwhpfan]

Their is not enough difference from 10-15 yards to make any difference. I think mathematically, the actual difference is like .000001 of an inch. That is within the margin of error for every pistol sight and eye combination ever made.

[Philip Dedmon]

Their is not enough difference from 10-15 yards to make any difference. I think mathematically, the actual difference is like .000001 of an inch. That is within the margin of error for every pistol sight and eye combination ever made.

Well said!

[Wormie]

Their is not enough difference from 10-15 yards to make any difference. I think mathematically, the actual difference is like .000001 of an inch. That is within the margin of error for every pistol sight and eye combination ever made.

Well some targets are covered with no shoots other the head A zone and small differences in point of impact is something I'm concerned about.

[9x45]

It's based on similar triangles, simple junior high school geometry. Let's say your 124's are 1" high at 15 yards, so 1" to 15 yards (540") is similar to X" at 10 yards (360"), therefore 1/540 = X/360, ie, .67" high, NOT .000001 of an inch. So it's only .33" lower, that's all.

[Lifeislarge]

No G34s I've ever owned have been accurate enough to measure the difference so it's a moot point. You act like you're expecting to lay down doubles in a match with a Glock lol.

[Nightops]

15 yards with a G34 on head shot only. If it is hard cover (black painted or black barricade in front of it), just put the big white blob in the chunky front sight on it an hope for the best. If it is a no-shoot (white target), fire 2 into the berm near it so you don't get an FTE penalty or hit on the no-shoot, and absorb the Mikes.

[9x45]

No G34s I've ever owned have been accurate enough to measure the difference so it's a moot point. You act like you're expecting to lay down doubles in a match with a Glock lol.

Huh? On a regular basis with my old 2 pin G17... It does have a hand fitted BarSto barrel, by Irv Stone himself.

Including a tripe I threw on a classifier. Problem is they are not always alphas....

[Craig N]

Problem is they are not always alphas....

Alot of my shots have that same problem.

[GrumpyOne]

No G34s I've ever owned have been accurate enough to measure the difference so it's a moot point. You act like you're expecting to lay down doubles in a match with a Glock lol.

Huh? On a regular basis with my old 2 pin G17... It does have a hand fitted BarSto barrel, by Irv Stone himself.

Including a tripe I threw on a classifier. Problem is they are not always alphas....

If you are doing that on purpose, you are obviously shooting too slow. My guess is those weren't planned...which makes shooting a double an accident, which may have been a product of a shakey grip, trembling trigger finger, or some other anomaly. ..

[9x45]

Shooting to slow? Really, give me a break, I wasn't born yesterday, and I have been shooting competition since 1967. How about you? I am able to do that at almost every match I shoot, usually 4-6 times a month, and I can't see holes beyond 7 yards. It's all about technique, all about the fundamentals. How many times can you have an accident? Most of my time I'm shooting 3-4" alphas, but again, I don't know that until it's scored. Doubles are no accident, they are a result of understanding the fundamentals. The triple was with my G31 carry gun running 125 grs at 1,420 fps. Nothing is "Planned" it's just grip it and rip it. I don't have a shaky grip, or trembling trigger finger, or some other "anomaly" whatever that is.

Just a guess, but maybe you need to get beyond C/D class to see that doubles are no "accident" on a regular basis.

Edited February 16, 2016 by 9x45

[d_striker]

It's based on similar triangles, simple junior high school geometry. Let's say your 124's are 1" high at 15 yards, so 1" to 15 yards (540") is similar to X" at 10 yards (360"), therefore 1/540 = X/360, ie, .67" high, NOT .000001 of an inch. So it's only .33" lower, that's all.

That's not how it works.

Using an inequality to solve a physics scenario generally doesn't work.

Edited February 16, 2016 by d_striker

[d_striker]

Using all of the inputs in OP, the correct answer is .1" low...

In other words, not even noticeable....

Edited February 16, 2016 by d_striker

[GrumpyOne]

Shooting to slow? Really, give me a break, I wasn't born yesterday, and I have been shooting competition since 1967. How about you? I am able to do that at almost every match I shoot, usually 4-6 times a month, and I can't see holes beyond 7 yards. It's all about technique, all about the fundamentals. How many times can you have an accident? Most of my time I'm shooting 3-4" alphas, but again, I don't know that until it's scored. Doubles are no accident, they are a result of understanding the fundamentals. The triple was with my G31 carry gun running 125 grs at 1,420 fps. Nothing is "Planned" it's just grip it and rip it. I don't have a shaky grip, or trembling trigger finger, or some other "anomaly" whatever that is.

Just a guess, but maybe you need to get beyond C/D class to see that doubles are no "accident" on a regular basis.

And what exactly is your class? As for how long I've been shooting, if you've been doing it since '67, you are a super duper granpa grandmaster?

No one is impressed with your "1420 FPS out of my carry gun" or your "I shoot 157 PF minor in my Production gun"...give it a rest.

[9x45]

It's based on similar triangles, simple junior high school geometry. Let's say your 124's are 1" high at 15 yards, so 1" to 15 yards (540") is similar to X" at 10 yards (360"), therefore 1/540 = X/360, ie, .67" high, NOT .000001 of an inch. So it's only .33" lower, that's all.

That's not how it works.

Using an inequality to solve a physics scenario generally doesn't work.

If the OP shoots it at 25 yards, it should be 1.66" high. True, trajectory is parabolic but he prediction is based on similar right triangles.

[ChuckS]

Unfortunately, I only have a 10 yard indoor range near me at the moment. There is a match that will require most shots to be at 15 yards. I didn't have any time to reload so I'll be using factory ammunition and I figure I'll sight in my glock 34 using this ammunition before the match. So I was wondering if I had sighted in for 15 yards, where will my bullets impact at 10 yards using 124 gr 1140 fps ammo? I'll try to compensate that amount when I sight in at the 10 yard range.

Go play with this to give you some idea. http://www.winchester.com/learning-center/ballistics-calculator/Pages/ballistics-calculator.aspx

This thing is giving ~ 0.3" low at 10 yards for their 124 FMJ 9mm for a 0.9" sight height. Not a whole bunch for iron sights on the clock.

[FTDMFR]

It's based on similar triangles, simple junior high school geometry. Let's say your 124's are 1" high at 15 yards, so 1" to 15 yards (540") is similar to X" at 10 yards (360"), therefore 1/540 = X/360, ie, .67" high, NOT .000001 of an inch. So it's only .33" lower, that's all.

That's not how it works.

Using an inequality to solve a physics scenario generally doesn't work.

If the OP shoots it at 25 yards, it should be 1.66" high. True, trajectory is parabolic but he prediction is based on similar right triangles.

Even if you were to approximate the trajectory as a straight line and use similar triangles, I think your analysis ignores the sight height over bore and puts the common vertex of the similar triangles in the wrong spot (it should be at the first zero, not at the muzzle).

If the OP is zeroed at 15, then at 10, he will be hitting low by about 1/3 of whatever his height over bore is.

Edited February 16, 2016 by FTDMFR

[ChuckS]

This thing is giving ~ 0.3" low at 10 yards for their 124 FMJ 9mm for a 0.9" sight height. Not a whole bunch for iron sights on the clock.

If the OP is zeroed at 15, then at 10, he will be hitting low by about 1/3 of whatever his height over bore is.

[FTDMFR]

I love when the back of the napkin matches the calculator.

Edited February 16, 2016 by FTDMFR

[d_striker]

Unfortunately, I only have a 10 yard indoor range near me at the moment. There is a match that will require most shots to be at 15 yards. I didn't have any time to reload so I'll be using factory ammunition and I figure I'll sight in my glock 34 using this ammunition before the match. So I was wondering if I had sighted in for 15 yards, where will my bullets impact at 10 yards using 124 gr 1140 fps ammo? I'll try to compensate that amount when I sight in at the 10 yard range.

Go play with this to give you some idea. http://www.winchester.com/learning-center/ballistics-calculator/Pages/ballistics-calculator.aspx

This thing is giving ~ 0.3" low at 10 yards for their 124 FMJ 9mm for a 0.9" sight height. Not a whole bunch for iron sights on the clock.

Using a sight height of .9" my ballistic calculator gives .23" low at 10y.

Is the sight height really .9 on Glocks? I originally used .5" for height as that's what most of my pistols are. This brings it back down to .1"

[selecw]

This thread is ridiculous. It's even linked to on other forums for that reason! There will be no practical difference. No more posts here please - go out and shoot more and you will know it's true

[Gooldylocks]

Shooting to slow? Really, give me a break, I wasn't born yesterday, and I have been shooting competition since 1967. How about you? I am able to do that at almost every match I shoot, usually 4-6 times a month, and I can't see holes beyond 7 yards. It's all about technique, all about the fundamentals. How many times can you have an accident? Most of my time I'm shooting 3-4" alphas, but again, I don't know that until it's scored. Doubles are no accident, they are a result of understanding the fundamentals. The triple was with my G31 carry gun running 125 grs at 1,420 fps. Nothing is "Planned" it's just grip it and rip it. I don't have a shaky grip, or trembling trigger finger, or some other "anomaly" whatever that is.

Just a guess, but maybe you need to get beyond C/D class to see that doubles are no "accident" on a regular basis.

This post gave me cancer.

Number one: you accuse people of needing "to get beyond C/D class" and say that it is "all about technique, all about the fundamentals," yet you don't know where your shots are going until you walk up and score the targets? If you are such an advanced shooter that has been doing it since dinos were roaming the earth, shouldn't you know how to call your shots, and know exactly where your hits will be before you score the targets? It would seem to me that with all this technique and fundamentals you are applying your doubles would be... you know... alphas? Go shoot some 25 yard bill drills and call every single shot out loud to your buddy, then go score it together. If they aren't exactly where you thought they were, maybe it is you that needs to apply the fundamentals.

Number two: Everything should be planned. Every draw, reload, sight picture, trigger press... everything. As soon as that buzzer goes off, you are purely on autopilot seeing what you need to see to make it stay on the plan.

Number three: I rarely have doubles, but I would be willing to argue that I have a fair handle on the fundamentals, and properly applying them during a stage. I think some would attest to that.

Number four: Grumpy is right. The whole "I shoot +P+ 357 out of my hand cannon and it makes me a big strong man" deal is getting a little long in the tooth. You shooting 250 pf or me shooting 130, doesn't matter when we are both getting scored the same.

[Youngeyes]

This thread is producing nothing useful. Closed.