You might want to check the crown for any defects.
It does not take very much of a ding in the crown to affect accurracy.
Do you have a mil spec extractor spring in your rifle?
Are you shooting off a bipod? Would also check the bolt carrier key to make sure it's not loose and/or binding with the gas tube. Somebody earlier said something about barrel could be loose and I would check this more closely with my AR tools, even if it didn't feel loose by hand. I knew a guy who had a similiar problem and it was the barrel. He removed the barrel and reinstalled it, this time with a little threadlocker (purple?) on the barrel ext and just inside the AR upper where the ext seats and problem solved. Good luck and hope you find your problem...
Have you always ran 69Gr SMK's? If it's been an issue since new it could be the load. My 1:9 hates 69SMK's. Bumped up to 73gr Bergers and all is well.Also,isn't horizontal stringing indicative of improper trigger control? Just throwing out another option.
I had a similar if not worse problem with a BM varminter; frustrated the shit out of me. I never did figure out what the problem was before I sold it. My dealer said it could have just been a crappy barrel.
You said your scopes were fine, but did you also check your base and rings?<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308sako</div><div class="ubbcode-body">
One of today's targets... And Thank You</div></div>
I had a similar if not worse problem with a BM varminter; frustrated the shit out of me. I never did figure out what the problem was before I sold it. My dealer said it could have just been a crappy barrel.
You said your scopes were fine, but did you also check your base and rings?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stiggy</div><div class="ubbcode-body">Have you always ran 69Gr SMK's? If it's been an issue since new it could be the load. My 1:9 hates 69SMK's. Bumped up to 73gr Bergers and all is well.Also,isn't horizontal stringing indicative of improper trigger control? Just throwing out another option. </div></div>I was going to say something close to this but the other way. 1:9 should like "lighter" bullets... Not heavier. Heavier bullets usually don't stabilize in a 1:9 very well. This isn't "etched in stone"... I've seen exceptions. Just a thought.
I think your barrel nut is loose -- not loose as in, ready to fall off, but loose, as in, it ain't tight enough. I've seen similar groups from other rifles with loose barrel nuts. Remove the gas tube and tighten the barrel nut, reinstall gas tube; problem vanishes.
1. Scope parallax set at improper distance (or shot at a distance that the scope is not set for with parallax), and inconsistant positioning of the head.
2. Shooting a load that is not at the right muzzle velocity for your rifle (the bullet is exiting the barrel while the barrel harmonics are causing a side-to-side motion).
3. improper/inconsistant trigger pull and follow-through.
4. holding and/or supporting the rifle inconsistantly from shot to shot. When you fire a group, do you do it all in one sitting while maintaining the same set-up and hold on the rifle, or are you letting go of the rifle in between shots?