[howie3601]

My S&W MP15 is for some reason shooting of to the right of my target by 4 - 5 inches at 50 yards.

I'm aiming at a MTN dew can in front of a 4x3 foot brown shipping box. I made sure my rear (Magpul mbus) sight was centered on the center mark adjustment. However as I said my hits are to the right of where I'm aiming. I adjusted the rear sight the the left about 6 - 7 clicks and it's now hitting on target at the MTN dew can fairly accurately. My concern is if this is normal for my rifle to do this? Wouldn't this indicate that either my barrel or AR front sight is canted? If so how do I confirm this or check through trouble shooting?

I'm think about taking it to a place that repairs firearms because it seems like a HUGE headache.
Any info would be greatly appreciated, thanks.

 

[LIKTOSHOOT]

Generally when I sight in any rifle for the first time I use a rest of some sort, be it mechanical or some improvised rest. You do not mention what stock you are using.
I suspect that since adjusting the rear sight and getting on target that your cheek weld is not correct. Not a big thing. Happens all the time when breaking in a new firearm.

When you use a rest you remove much of the human error as possible. I also have a rest that removes all human error as you do not touch the rifle as it has a remote trigger release. That was what we used to verify the potential of any given firearm we were building and matching to ammo.

 

[Old Guns]

That is the exact reason a gun has adjustable sights. Try different types of ammunition and see if it shifts the point of impact again. Then you can adjust the sight for that ammo. Unless the sight is set way to the left or right there is not really anything to worry about. Contrary to popular belief all barrel are not bored 100 percent straight.

 

[gdmoody]

Have you tried other sights. In my humble opinion, it is the sight. I am sure you know that Magpul makes (or used to) two varieties of that BUS, one for "BB guns" and one for real AR 15 rifles. I got one once for a great price but could never get it to sight in, it turned out the great price was because it was for an "airsoft" gun and not a real AR.

You would almost have to have a bent barrel to shoot that far off and that is pretty much unheard of, so try another sight before you send the rifle to a gunsmith for what could be a really easy fix!

 

[The_Rifleman]

There is nothing wrong with your rifle. Different ammo will have different point of impacts; and the only way to know where they will hit, is to shoot them and see. That is why they make adjustable sights.

 

[68c15]

I think your cheek isn't up on the stock and your eye isn't centered (in line with barrel center). Take upper off, remove bolt carrier, set it in a pair of matching rests then look through bore lining it up with target. As you look though it the front end will appear smaller than rear, get small front centered in larger rear. Then without touching or moving upper look through sights. They should line up closely with target

 

[FRED J. WAHL]

All good advice! I would add one more thing to check, and that would be try different ammos, as some ammos in the same caliber will pattern to a different "POI" (Point of impact)
I remember a British .303 SMLE I had bought from S.O.G.,years ago, the bore was fine, but it wouldn't even get on paper at 100 yards. The only option I had was to tap the front sight to the left, as far as it could go, to move the strike of the bullet to the right, and it STILL would not get onto the black. That was the ONLY gun I have ever sent back to the dealer, for a replacement. The replacement I still have, and it's a good shooter.
Fred (Honcho)

 

[jedwil]

So, if I read what the OP wrote correctly, he fired his rifle for the first time with open sights. The rear sight was in the middle and the POI was a few inches to the right of his point of aim. He adjusted the rear sight a few clicks and the POI is at his aim point. Sounds like everything is working just fine.

 

[woolleyworm]

My main and first concern when sighting in any rifle/ammo combo is getting repeatable groups. I don't really care where they're at. Once you get groups, you can diagnose potential problems.

 

[howie3601]

My main and first concern when sighting in any rifle/ammo combo is getting repeatable groups. I don't really care where they're at. Once you get groups, you can diagnose potential problems.

What kind of groups should I be looking at with my Barrel at 50 yards (Realistically) with an M&P 15? I was getting 2 and 3 shot 1 - 1.5 inch groups, because I was able to hit the MTN Dew can with no issues. Keep in mind I only key holed a few hits when I fired a total of 60 round through an hours time.

Also that's my rear sight's current adjustment for anyone that needs a reference of where I'm at. I always found the windage adjustment to be a little pointless (since in combat I can't see it being used) That's why I was wondering if the rear sight isn't just for windage or is it for both?

 

[68c15]

Hold on a minute. You are getting key hole shots?! I think we may have found th problem. A key hole shot is when the bullet hits target sideways, not with the tip or point. That is some real bad loads.

 

[howie3601]

S

Hold on a minute. You are getting key hole shots?! I think we may have found th problem. A key hole shot is when the bullet hits target sideways, not with the tip or point. That is some real bad loads.

Sorry I mean the POI is the same or almost the same.

 

[jedwil]

What kind of groups should I be looking at with my Barrel at 50 yards (Realistically) with an M&P 15? I was getting 2 and 3 shot 1 - 1.5 inch groups, because I was able to hit the MTN Dew can with no issues. Keep in mind I only key holed a few hits when I fired a total of 60 round through an hours time.

Also that's my rear sight's current adjustment for anyone that needs a reference of where I'm at. I always found the windage adjustment to be a little pointless (since in combat I can't see it being used) That's why I was wondering if the rear sight isn't just for windage or is it for both?

Windage is merely the horizontal adjustment of your sight. It moves the point of impact from left to right and is very important. You successfully zeroed your rifle if it is now impacting where you are aiming. Shrinking group size is another complicated matter.

 

[zant]

I sight in using 5-10shot groups-3shots doesn't tell you anything.I shoot the group-not caring where it hits-as long as it's a tight group-then adjust sights accordingly...Try this-sight in using 55gr-after everythings adjusted properly-shoot a group with 856 rounds-it will be 3 times as big and many inches to the L/R.Different ammo-different POI.

 

[gdmoody]

And try using a paper target so you can track your hits, not a mountain dew can.

You know that Mountain Dew will rot your teeth.

 

[jim brady]

The guys telling to use a PAPER target and to FIRE FROM A SOLID, SUPPORTED REST are dead-on.

Bullets impacting a couple of inches off target (even at 50 yards) from a new or non-zeroed rifle shouldn't surprise anyone. Compound that with using a tin can as a target from an unsupported firing position - and you end up exactly where you are.

If you are trying to 'zero' or set your sights - the ONLY way you can do this is to fire on a paper target at a known distance. If you are not using a firm, supported firing rest, you are wasting your time and ammunition. If I were doing what you are trying to do, I'd set up a paper target at 50 yards and fire a 3 or 5 shot group (either firing from a shooing bench or a prone firing position with the forward shooting hand supported). I'd adjust my rear sight so that the group is centered over the target's centerline. Then I'd fire another group, with the intention of centering that group about 3/4" below the bullseye of my 50 yard target.

By doing this, my sights would be set to hit anything from point blank range to about 250 yards with the bullet striking within just a couple inches high or low.

Someone brought up the fact that there are hundreds of rear sights made for AR rifles - some of those are made for BB guns or toys and are incredibly cheap. Avoid those and use sights made for real rifles.

 

[LIKTOSHOOT]

I would add just one more thing to this problem. Generally and that would be in the high 90% area, loads do not shoot left or right. They string vertically or shoot high/low given the weight and brand of ammo used.

 

[jim brady]

'Wish I had a nickel for every guy I saw "chase groups" in trying to zero a rifle. Most people over-think the problem. All you need is an aiming spot on a paper target and a good firing rest. Slowly fire 3 shots - concentrating on the aiming spot.

Go down range and check out your target. You should have 3 bullet holes nearly touching each other. Doesn't matter WHERE on paper they are, so long as those 3 holes are close to each other. If those holes are NOT close to each other - the problem is not the rifle's sights (that is unless of course if they are nor broken or loose) - the problem is the shooter.

If you have 3 shots close to each other, all you need to do is to move the rear sight on your rifle to what ever direction (sideways or up or down) to shift the impact (bullet holes) to the original aiming point.

 

[68c15]

'Wish I had a nickel for every guy I saw "chase groups" in trying to zero a rifle. Most people over-think the problem. All you need is an aiming spot on a paper target and a good firing rest. Slowly fire 3 shots - concentrating on the aiming spot.

Go down range and check out your target. You should have 3 bullet holes nearly touching each other. Doesn't matter WHERE on paper they are, so long as those 3 holes are close to each other. If those holes are NOT close to each other - the problem is not the rifle's sights (that is unless of course if they are nor broken or loose) - the problem is the shooter.

If you have 3 shots close to each other, all you need to do is to move the rear sight on your rifle to what ever direction (sideways or up or down) to shift the impact (bullet holes) to the original aiming point.

I agree for the most part. But if the loads are not real consistent neither will your shots. I have seen factory hunting loads with more than 10% variation in powder charge. Plinking rounds are even worse. This gets you vertical strings like you mentioned. But at longer distance you get barrel whip, that can make shots go in circles. I'm not a pro by any means, just relaying what I've seen first hand

 

[mogunner]

You're not left-eye dominant are you?