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View Full Version : Point blank out to 50 yards..margin of error?


NYY
06-23-2011, 10:05 PM
So i just had a first hand experience on how my sights really work. Skunk issue, took AR, 3 shots, 1 of them actually hit his chest as i saw post:killing. not dead, but injured. I got mad at that point. took .22, point blank, out of its misery. I had to. i felt bad enough that i did not kill with 3 shots from ar15. My point, the iron sights i have now are sighted in at 50 yards, obviously, with the muzzle touching a wall, the sight picture through the irons is about 2 inches high = an inaccurate shot. For example, putting the sights on a skunk at about 15-20 feet, i clearly missed. Should i have thought of this before i went out? Or Was i right to go with my first thought of (well, i should be close enough, that the sight picture wont matter) ?..which proved to be wrong... Just puzzled on situations like that in real life when weapons are sighted in at long distances but are sometimes used at close range. What should you do in that situation?? And i do realize that if it were a HD situation.. the margin of error at that distance would not matter because the target (unfortunately if it comes to it- a person) is so large that the bullet would hit close to sight picture..

p.s. i honestly feel like a terrible person for taking 4 shots at 1 skunk. Major human error there.

fuenstock
06-23-2011, 10:21 PM
If your zero is at 50 yards, then at 15-20ft you will have to aim some where around 2-3" high to hit your target. Its called mechanical offset. My rifle is around 3" low at 3 yards with a 50 yard zero, but your could be diffrent depending on your seup.

THT
06-23-2011, 10:27 PM
50yd zero at 5yards will need to be held 2-2.5" high. This is the height over bore issue. At 15 yards, it's close to 1" and between 25yds and 50, POA is pretty much POI.

Rukus
06-23-2011, 10:59 PM
Should i have thought of this before i went out? Or Was i right to go with my first thought of (well, i should be close enough, that the sight picture wont matter) ?

I don't mean to offend here but are you serious? Anytime you pull out a firearm with the intent of killing something you better know where your rounds are going to go.

Are you really a Marine? I would think that would be a basic part of training. I took an intro to carbine class and that was one of the first things that was covered in class.

NYY
06-23-2011, 11:03 PM
Ahh i see. So there is an actual term for this.. "height over bore". Awesome! i love it thanks guys. Have always been curious about that

NYY
06-23-2011, 11:07 PM
I don't mean to offend here but are you serious? Anytime you pull out a firearm with the intent of killing something you better know where your rounds are going to go.

Are you really a Marine? I would think that would be a basic part of training. I took an intro to carbine class and that was one of the first things that was covered in class.

read the sig.. and yea, at first i believed the round would be on target if lined up in sights.

G-forceJunkie
06-23-2011, 11:09 PM
The bullet only crosses the line of your sites at two points, anytime your not shooting at those two exact distances, its going to impact higher or lower. If you know the height over bore of your weapon, and the ammo your zeroing with, you can plug it into a free online ballistic caculator and get a graph of the bullets flight.

edit: there are several here: http://www.ar15.com/content/page.html?id=660

pyro3k2
06-24-2011, 12:35 AM
Zero your rifle at 25 yards next time. If you are concerned about HD and close range shooting, than a shorter zero would be the way to go. It won't get you to be pin point accurate at every distance, but your shots will be much closer to you POA

jeffrice6
06-24-2011, 12:57 AM
Anytime you pull out a firearm with the intent of killing something you better know where your rounds are going to go

This!!!

THT
06-24-2011, 1:40 AM
Zero your rifle at 25 yards next time. If you are concerned about HD and close range shooting, than a shorter zero would be the way to go. It won't get you to be pin point accurate at every distance, but your shots will be much closer to you POA

25yd zero vs. 50yd zero for CQ really doesn't have much of an impact however at longer ranges, the 25yd zero will be absolutely terrible. 50yd is the better choice between the two.

negolien
06-24-2011, 2:43 AM
You shoulda Asked Whitey Bulger to give you some tips as he was in your area LOL...

FLIGHT762
06-24-2011, 8:46 AM
You just learned about sight offset on an AR-15. If you want to hit something the size of a ping pong ball at 20 feet away, you have to take sight offset into consideration and aim about 2.5" high. When shooting a regular rifle like a Ruger 10-22 with open sights, sight offset is minimal. Because of the design of the AR-15, sight offset has to be taken into consideration when shooting at very close ranges or shooting over barriers.

Next time you're out, set a paper target out 20 feet away. Draw a 1/2" circle and shoot it with your AR. You'll see what your offset is. As you get closer to your zero distance, the offset will get smaller (shorter), but at very close range, you have to aim high.

d4v0s
06-24-2011, 9:25 AM
Also you mention that you hit it in the chest with the AR. I used an AR15 on my ranch to kill yotes, and skunks. Its a good idea to get some decent ammo like a heavy hollowpoint or a softpoint hunting round. FMJ will just go through it like hot butter.

Maddog5150
06-24-2011, 9:43 AM
read the sig.. and yea, at first i believed the round would be on target if lined up in sights.

Not everyone has sigs enabled. Too man people have large GIFs, huge pictures, endless quotes from other members or people trying to look cool by listing out thier collection.
I turned them off long ago so from your screen name, I would assume you are a Marine also. If not, why make a screen name with that in your your name? Thats like putting, "high_profile_banger" in your name.

NYY
06-24-2011, 5:42 PM
Also you mention that you hit it in the chest with the AR. I used an AR15 on my ranch to kill yotes, and skunks. Its a good idea to get some decent ammo like a heavy hollowpoint or a softpoint hunting round. FMJ will just go through it like hot butter.

ya thats why i was wondering how this guy didnt die when i actually did hit him. only saw a clean hole through it

MrOrange
06-25-2011, 5:37 PM
Surprised nobody mentioned this, (or is it a grammar nazi kinda thing?), but the term "point blank range" refers to the greatest distance you can shoot and not have to hold over to stay within the acceptable impact area. It will vary with zero range. For example, with a .357 revolver zeroed at 75 yds, point blank range for social use will be around 100 yds.




25yd zero vs. 50yd zero for CQ really doesn't have much of an impact however at longer ranges, the 25yd zero will be absolutely terrible. 50yd is the better choice between the two.
That's interesting... When I was in, we zeroed our A1s at 25m. The second crossing came at 250m, and you had to hold at shoulder height at 300m. What range does the Army zero their M4s at nowadays?

Drivedabizness
06-25-2011, 7:46 PM
it was actually 1000 inches for initial battle sight zero.

If you are zeroed for 100 yards - the bullet is still rising (aka low) at 50. But you should be within an inch.