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Typical? Windage-elevation issues
12/28/2011 8:33:45 PM
So, went to sight in my Sig 556 classic today. Set up at 25 yards with the typical M4 zero target. Was firing from a seated position, using the magazine and gripping around the magazine well. Initially, 2-3 shot groups were both to the left significantly. So, I put on the expected dope and brought it right no problem. It was also a bit high... so I then adjusted the rear sight drum (sights were on 300 the whole time, this was the drum sight) for elevation.
I came down about 7 clicks. Fired another 3 shot string. Groups are back at the SAME POINT that I initially started at. As if I'd put no wind at all on...though now, the elevation is correct. Hoping it was a fluke, I fired another 6 shots... All in the same place. Took my rear sight ALL the way to the right and ended up just barely touching the left shoulder of the zero ring. I had to make a front sight adjustment to actually get the last few increments I needed. However, I have no right wind left and my front sight is several millimeters to the left.
Looking from the front, I notice that the picitinny rail on which the rear sight is mounted appears to be slightly canted. Is this typical? If so, what's Sig's track record on fixing it? It would seem to explain the windage changing with an elevation change.
1/7/2012 11:03:22 PM
Nobody?
1/8/2012 5:33:14 AM
Same issue here 
I have to position the front site all the way left and the rear site all the way right to get it at POA. A pain in the arse to send back a $1200.00 gun for something that should have never left the factory. I have to call on Monday for a RMA
I have to position the front site all the way left and the rear site all the way right to get it at POA. A pain in the arse to send back a $1200.00 gun for something that should have never left the factory. I have to call on Monday for a RMA1/9/2012 8:44:43 AM
Realy wierd!
That much out of alignment would mean the rail is so canted it would look like it 45 degres off. The front sight moves the impact point of aim about half inch as does teh rear sight. Heck, if you look down the gun the barrel would look like it was out of alignment with the receiver that you could see it clear as day. I have four 556's and a 551A1 and none have a sight alignment problem, especially like you are describing.
I had a PTR 91 do exactly what you are describing and upon inspection I cound see that the trunion/barrle was pointed to the right and I really mean see it. You could see the barrel was out of alignment with the receiver by about 3 degrees to the right. But the PTR 91 has a stamped steel receiver and not forged and machined like the Sig 556 or Ar 15 type guns.
That much out of alignment would mean the rail is so canted it would look like it 45 degres off. The front sight moves the impact point of aim about half inch as does teh rear sight. Heck, if you look down the gun the barrel would look like it was out of alignment with the receiver that you could see it clear as day. I have four 556's and a 551A1 and none have a sight alignment problem, especially like you are describing.
I had a PTR 91 do exactly what you are describing and upon inspection I cound see that the trunion/barrle was pointed to the right and I really mean see it. You could see the barrel was out of alignment with the receiver by about 3 degrees to the right. But the PTR 91 has a stamped steel receiver and not forged and machined like the Sig 556 or Ar 15 type guns.
