FNAR heavy 20" barrel, Burris signature Z, Sightron SII Big Sky 3.5-10X42 
I have been chasing the zero for six months. First I thought the rings were the problem (Burris signature Z), but I fixed the slipping problem with some rubber cement. Next, I thought the base was loose. So, I bedded the rail and retorqued with locktite. Ammo, I tried WRA, PRVI, Remington match, FGMM, and the best I got was a 4"-5"plate.  Next, maybe the shooter, so I had my buddy shoot the rifle (bullseye shooter), still 4"-5" plate (this guy can shoot 2"-3" groupings using iron sights on a FAL).  Maybe the gun?  Used Burris Fastfire to get 3" groupings.  Well I did what I should have done first. Tried a different scope with everything else same. 
1" groupings. 
Add insult to the injury, the windage knob came off. Called Sightron, told me to mail it in. That was a week ago, no indication they got the scope. 
Anyone else deal with sightron scopes?
			
		
