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-   -   Zeroing at close range (http://www.firearmstalk.com/forums/f20/zeroing-close-range-87002/)

StainlessSteel215 03-20-2013 04:53 PM

Zeroing at close range
 
So I'm new to the rifle platform and have a zero question....

If I am forced to zero at my local indoor range (25 yards) and want to zero my sights to 75 yards.....how many inches above target should I be?

SSGN_Doc 03-20-2013 05:16 PM

What rifle, caliber and scope? At 25 yds you most likely want to be a little low, because the bullet hasn't hit it's apex yet and started to drop. Bullets travel in an arc, going up and then dropping. So you would need to know the trajectory if the round you intend to use and the distance you want to be sighted in for. Then you have to account for the height of the sights over the bore. There are ballistics programs that will get you pretty close if you put in the cartridge data, and sight height, along with the distance you want to be zeroed for. Some will tell you how high the bullet should be at your sight in distance for a given zero range.

StainlessSteel215 03-20-2013 06:09 PM

Ar-15 using mainly 55gr .223 rounds

No scope, most likely an non-zoom optic which is why I want no more than 75yards for a zero. I plan on shooting mainly between 25-75 yards

So, while zeroing at 25 yards for a 75 yard trajectory I was thinking it needs to be pretty close to point of impact.....maybe slightly above target?

Sniper03 03-20-2013 07:27 PM

OK.
Lets see some picks of the rifle. To be zeroed close to 50 as well as 100 yards. You should be hitting close to the following. One could measure the distance between the top of your front sight post and the center of the bore at the muzzle. For example if it measure 2 1/4 inches. Then when shooting dead center at the bull on the target the bullet should be sticking around 2 1/4 inches low of the aiming point at 25 yards. That will put you in the ball park at 50 and 100 yards. You might have to make some minor adjustments at those ranges but you would be on target. How I do it is I draw a Black Cross for example 2 1/4 inches below the center of the target and that is where the bullets should strike.

03

AgentTikki 03-20-2013 07:39 PM

For irons, I'd stick with a 25 yard battle zero. Is there any particluar reason why you want to have it zero'd at 75 yards?

StainlessSteel215 03-20-2013 08:18 PM

I dont anticipate shooting beyond 75yards. Thats the furthest my outdoor range stretches....plus for practical combat uses I estimate that it would occur within 50 yards.

What is your opinions on a practical zero distance considering a comfortable middle ground between long range and close range combat. Thats how I settled on 75yards

SSGN_Doc 03-20-2013 10:39 PM

Look up the improved battle sight zero for AR 15. It is a 50 yd zero, which would have you hitting a slightly low at 25 yds and right on at about 200yds and then about 2" low at 300 yds. Between the muzzle and 300 yds you wouldn't be more than 2" high or low. So 75 yds would be pretty close at that zero. I also think there are targets scaled for AR rifles to get you the IBSZ at 25 yds. If you use one if those targets then adjusting your sights to hit the designated point of impact would have you right on.

kbd512 03-23-2013 06:41 PM

Unless you are a military user, I would stick with your 25 yard zero and perhaps even consider a 10 yard or 15 yard zero.

Lot's of people talk about realistic combat ranges who are intellectually dishonest about what those ranges really are. The overwhelming majority of evidence that I've seen would seem to indicate that virtually all engagements for civilians and police officers against armed criminals take place inside 25 yards with most being just past 7 yards or so. Even the military, mostly due to the continual build up of urban areas, gets into lots of gunfights that are less than 100 yards.

You're concerning yourself over a matter of a few inches and the likelihood of you having to make a shot over 25 yards is virtually nil if you are not a military user. If you aim for the center of someone's chest and hit them a couple inches high or low, do you think your hits will be ineffective?

If it were me, I'd consider a 10 yard or 15 yard zero. It's far, far more likely that you'll have to use your carbine at bad breath distances than it is at 100 yards. Do what you like with your zero, but be honest with yourself about the distances that you'll likely use your carbine at for personal defense if it comes to that.

If you don't know what realistic personal defense ranges against armed criminals are for civilians and police officers, there has been quite a bit of evidence collected on the subject and you can find it with Google and you may or may not have to purchase a report from a study or two on the subject. Our government is quite helpful with respect to its collection and publishing of crime statistics. Our government counts more beans and is more detailed in their bean counting process than any other entity on earth that I know of, but no one ever seems to bother to read all that information to benefit from it.

If it were me, I would have no problem with a 15 yard zero, which is what I use. I've even contemplated a 10 yard zero because I think even 15 yards is at the far end of my realistic use for my personal/home defense carbine. If I ever have to make a 100 yard shot, all I have to do is aim a little higher (to be completely honest, I won't bother aiming any higher or lower as I'm just going to put my sights on the center of the target and squeeze the trigger - who cares if I'm two or three inches low).

StainlessSteel215 03-23-2013 06:59 PM

Great post KBD, and very much appreciated. Truth is I am brand spanking new to the rifle platform so I am definitely not dead-set on a longer range Zero. I just thought it would be a good negotiation between short and long range. When it comes to combat, sure I understand most battles happen at close distances but this will NOT be the weapon of choice for home defense or close range. Thats what the shotgun is for. I would like to ability to hit long distance targets for practice

kbd512 03-23-2013 07:35 PM

I highly recommend professional training for using your AR-15 if you intend to use it for any non-sporting purpose. Most reputable firearms instructors will tell you the exact same things I've previously stated, but it's better to hear it from their mouths than from some random guy on the internet that you know nothing about.

A lightweight AR-15 carbine with a red dot optic is a fantabulous home defense weapon with the right ammunition (plain Jane 55 grain FMJ), professional instruction in its use, and consistent practice (which is always the case with any firearm). There are lots of myths surrounding the AR-15 vs 12 gauge shotgun about penetration, aiming, the effects of the ammunition on soft/hard targets, what loading is best, and so on, but professional instruction will quickly help you decide which weapon ranks first for home and personal defense. That said, a shotgun can be a perfectly usable tool that serves the purpose.


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