Hey guys, I've got a SIG 516 that's giving me some pretty weird results. It functions flawlessly, but the trajectory sucks. It's level at about 25 yards, but then around 2 feet high at 125 yards. I'm using Federal 5.56x45 55g NATO stamped. My barrel is a 1/7 twist, is it the ammo I'm using? Does anyone else have this problem?

...two feet sounds a little excessive, but a certain amount of rise at that range is to be expected - but it all depends on your zero.  Where did you zero at?  

You did zero the rifle, didn't you?
 




~Augee

I zeroed it at 25 yards. I called SIG and they also said to zero it at 25 yards. I'm completely stuck and confused. I literally just shot it again and my target is one foot high, my bullet was striking at least 1+ foot over it.

Are you using iron sights ?

Try adjusting the front site so you are zeroed at 100 yards

Wulfmann

I'm using the red dot sight that came with it, I forgot the brand. I want to say its a sightmark. But I've put a scope on it and still got the same results.

Man!  I have Four 516's and no problems like that.   Mine are 2 Gen 1 and 2 Gen 2's

Could it be the bullet weight? 55 grain might fly higher than a 62 grain, is your rifling 1/7? Sounds like it might be an issue wit the sitemark reddot though...is it snugged good to the rail?

not bashing and i love my Sig516, try zeroing with the irons, but the Sig red dots have had less than stellar reports, i ended up putting a T1 on mine. this is just me, but i would verify zero with irons, and try a different red dot. see if a friend can let you borrow a red dot and see what kind of groups you can get.

Your title is quite misleading.  You don't have a problem with the gun, you have a problem with the user.

First thing you need to know is the yardage you want it to be sighted in.  The 25 yard sight in is just to get it on the paper at your actual sight in distance. Since you have it on the paper now you are ready to sight it in at your actual sight in distance.
#1  Place a target at your preferred distance.  (200-250 yards is good with a dot or irons)
#2  Shoot bullets at target and adjust your sighting device to put it on the bulls eye.
If you don't have a place to shoot 250 yards you can just sight it in a couple of inches high at 100 yards, or 125 yards, whatever.  I am sure it will be close enough for you to learn basic techniques.

zero so that bullet hits about 1.25 inches below the bullseye at 25 yards, look at the graphs posted above.

you are the red line on the graph, you want to be the green line hittint the bullseys at 50 yards NOT at 25 yards

mbell, He is already hitting the paper at 125 yards.  Why would he want to dick around and waste any more time zeroing at 25 or 50 yards?  Or do you just zero at 50 yards and call that good enough?

That's what I was thinking. Maybe 55g is too light? The sight is snug on the rail, won't budge. At close range though, the red dot sight is spot on.

This is the only rifle I've ever had problems with. I sight in every gun that way, including my M14 and it's always spot on. 25 yards is supposed to be when the bullet is level, then it levels back out at somewhere around 150 yards. The point is, the gun is messed up or my ammo hates me gun. Not a user error.

Yes, definitely user error.  25 yards is not the right distance to zero that rifle for a 150 yard zero.  Stupidity can't alter the laws of physics no matter how hard you try.
Zero it at 50 yards and then come back and tell us your results.

Wow, so many opinions. With most 5.56 ammo, a 50 yard zero will provide the least amount of deviation from the target out to about 300 yards. Depending on your bore to sight axis, less than 50 yards rounds will be from 0 to 2 inches low. They will be high between 50 and 200 and then low after 200. This has proven to be the best combat zero for irons and un-magnified red dots.

Yes.

A 25 yard zero with standard height AR-15 sights will put the bullet ridiculously high at the mid point which is exactly what the OP is getting.  This is not rocket science.

@wildnfree, no point in being a dick. I'm doing what SIG told me to do. The problem is most likely the ammo. SIG told me that if I'm using 55 grain ammo then I need to move the sight up about an inch at 25 yards. They said the gun IS SUPPOSED TO BE SIGHTED IN AT THIS RANGE AND LEVEL OUT AT 125. They said 62 grain shouldn't have this problem. All I have to do is wait on some ammo and test both weights.

Me being a dick?  LOL.  Sig is wrong and you will remain at the special education level of intelligence regarding the ballistics characteristics of the 223/556 round as long as you listen to them instead of the experienced people on this forum.  The problem is most definitely not the ammo or your rifle.  There is virtually no practical difference between the trajectory of 55 gr and 62 gr ammo out to 250 yards.
Why do you need to test 'both' when you have already tested one and instead of getting the results you expected you got the results we said you would, and told you what the problem is.  But you are so hard headed that you won't even correct your problem with the correct advice that we gave you, and you are still trying to blame your problem on your rifle or ammo.  IF you actually knew anything about sighting in a rifle you would know that what the bullet is doing at 25 yards (or 50 yards) doesn't mean squat anyway when the target you really need to be able to hit is at 200/300/400 yards.  If you sight it in to hit your target at the longer range you will be right on track at the closer distances.  Have you ever heard of 'point blank range'?  Here is a link for you to play with if you are interested.  The figures on the chart are what you should get with a 50 yard zero.  The PBR figures can be pulled up by setting the correct parameter in the box if you had rather sight in that way.  Just click the calculate button at the bottom of the page when you get to the link.  http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi
I also have my doubts about your measurements.  If you actually did sight in your AR at 25 yards the bullets will not be hitting over 12 inches high at 125 yards.  Did you actually measure this distance or just make a wild ass guess?  For the bullet to hit 12 inches high at 125 yards would require a 20 yard sight in distance (zero).  



Once again, Sig is wrong.  Sig builds guns. The people on this forum shoot them.

IF you use a 25 yard zero it won"t level out till it reaches approximately 225 yards at which point it will be approximately 9  inches above the line of sight, and then it will cross the line of sight again (zero) at around 400 yards.  To get it to level out at anywhere close to 125 yards would require a zero of around 50 yards (225 yards).
I also noticed your previous post said that it levels out at 25 yards and then levels out again at 125 yards.  Wrong.  A bullet only levels out once at the very brief instant it reaches it highest trajectory.
Also, just because you always use a 25 yard zero on all your guns, including your "M14" and it has always worked fine just shows you how lucky you have been in the past, but your luck has run out.

If you will  study the charts provided above in this thread and at the link maybe you will understand what we are trying to tell you.
 

I get the charts, but that isn't what's happening with mine. If my method of sighting in was wrong then FM 23-9 is wrong too.

Go to page 50 of FM23-9 and read and understand.  Look at the pictures.  A 25 yard zero is for iron sights, specifically the LONG RANGE reticle.  
Do you see in the quote below where it says:
" After making this adjustment and flipping back to the short-range sight and aiming center of mass at a 42-meter target, the bullet crosses the line of sight at 42 meters and again at 250 meters as shown in Figure 3-22."
This is the result you want with your RDS since YOU DON'T HAVE A LONG RANGE FLIP UP RETICLE IN YOUR RDS for long range sighting.  Also, they are sighting in at meters.  Since you are using yards you will need to convert meters to yards so you would end up with a zero range of 42 meters plus 4.2 which equals 46.2 yards short range and 250 meters plus 25 or 275 yards long range."
Read this from page 51 and understand.  Convert meters to yards to get correct distance.

Notice they say to aim 1" low at 25 meters.  This puts your zero at approximately 46 yards.  [This is also the same Point Blank Range sighting method I was talking about in my previous post].



A person with a closed mind repeats the same mistake over and over and wonders why he doesn't get a different result.

On my Sig 516, I did the 25/50 yard zero. This is the target you place at 25 yards with a green bulls-eye dead center and another grey bulls-eye about an inch or so lower than the green one. You aim at the green bull-eye and adjust until your impacts are in the grey one. This target effectively nets you a 50/200 yard zero which has the smallest amount of overall deviation in trajectory from 25 to 300 yards. With this method, I have not experienced any of the issues you have reported. Try it and report back.

Here is the target:



http://www.ar15.com/mobile/topic.html?b=3&f=18&t=529846

Here is a great PDF on the subject:

http://gunwebsites.net/wp-content/uploads/2011/09/Guns-AR15-Zero-Introduction.pdf

This is pretty much what I was hoping for, I'll try it when I get good ammo. I only have a handful of Wolf left. So as soon as I can find some federal ill get it the.n try it with this target. Thanks!

You don't need good ammo to confirm whether or not this works. Once you do the 25 yard zero, you will only need about three shots at the longer distances you mentioned earlier to confirm whether or not this worked for you.

I used TulAmmo. Sure, better ammo will be more accurate and precise, but you were so far off the mark that if you start hitting paper at longer ranges with the cheap stuff, that should be all the evidence you need to come to the conclusion that the Sig recommended 25 yard zero was a bad recommendation.

With that said, I'll be shooting as soon as the weather clears up. Thanks for posting that, I was beginning to worry.

This.

The target fixed it. It's dead on now and good for any distance. You relieved A LOT of frustration. Thank you!

I just used one of those yesterday, works really well.

LOL.  "IT" wasn't broke, so the target didn't fix "it".
All the target did was put 'your' problem in simple enough terms for you to understand so 'you' could turn the little screws to fix 'your' problem.

But I am glad you finally figured it out.

Now you can accurately change the title to "Problem with the shooter; " Sig 516 great!!

Wulfmann

Agreed. OP should change the title of the thread. There was no problem with the Sig.

 You've seen combat with that zero?

 Zen of the 100 yard Zero by this guy who puts on a hell of a carbine class.

Totally confusing unnecessary BS, which is why no one uses that method.