Problem: If i zero it at 50 yards, at 200 it is 6-8" high. If i zero at 200 it is 4" low at 50 yards.
Are you using the military 25 meter zero target? Point of aim and point of impact should be different on these, but they are helpful to use.
The groups were fairly tight and consitent.
If your groups are tight, and if the above is correct; all of your issues are in elevation; correct?
I am suspecting the PEPR mount is over tourqued or bad, or the barrel is not seated properly.
PEPR mounts can be an issue, but if it is the PEPR, then your groups might very well open up in both directions. As you stated earlier, you have tight groups, but are off in elevation.
First i am going to remove the scope and mount then zero with irons.
I highly highly reccomend this as your first action. With the PEPR off you can take a look at it and see what you have going on and if it is an issue with the mount.
If it zeros 50/200 normally, then i can iliminate the barrel as the issue.
I have had a barrel on a Sig 556 Swat Patrol that was mounted inccorectly. It was so wildly off that at wouldnt stay on paper and it drove me nuts for an hour or so. If you have an issue like this, usually the problem will be off in both elevation and azimuth, not just in azimuth. In other words when the barrel is canted it is usually off center in more than one single direction. You can check this easily if you have a laser boresighter and you can do it at home and save some ammo.
Any other ideas?
Always start with one issue at a time, otherwise someone will find you in a straight jacket, mumbling to yourself at the mercy of Nurse Ratchet.
1)Start with your irons. (Do the laser boresighter if you like, just to eliminate any doubt about your barrel, but I doubt it is the issue. You just need to see that you aren't wildly off center here.) Get the military 25 meter zero target on line and make about 5 copies. Read the instructions and keep a copy by your rifle as you zero.
2) As you zero only move in one direction at a time. Elevation first and Azimuth second is the way I do it.
3) Note that as you fire your point of aim and point of impact will be different.This is cool, because it turns your 25 meter zero in to a 100 meter zero.
4) Once you get this right your irons are zeroed and you can work your glass.
Check your rig, everything Square? are the screws on your rings tight and do you have blue locktite on them? Are the QD released at the appropriate setting/tension to hold zero,..do they wiggle?
5) Lets not mess around now, fire three rounds at 50 meters through your glass and get the azimuth adjustments right then go ahead and take it out to 100 meters.
6) Once again move azimuth first if necassary, then do elevation adjustments. I like my zero on an M4 to be two inches high at 100 meters but YMMV, tweek it in at 100 and you should be fine.
My PEPR mount gave me a bit of a problem finding a tension adjustment it liked, once it was in though, it was fine. My big issue was craning my neck to get the hold I needed to get high enough on the glass, but thats for another day.
Good Luck
