Burris FF3 no holding zero

[BBD]

Installed a FF3 with speed bead on my dads M2 20 gauge today.  I have checked everything and it will not hold zero.  I have tried turning and twisting everything on it and cannot make it move but when shooting heavy loads it will move.  Has anyone else had this trouble?

[Rem Man]

   I would first check to make sure everything is nice and tight. I would then put the gun in some type of vise or steady hold. Put the dot on a bullseye and move all directions up down left and right to see if the dot is moving correctly. If it works throughout this test call burris, they will take care of you. They are a fantastic company!!!! 

[Rem Man]

 Forgot to add, make sure you magazine cap is tight and your barrell is not moving.

[howl]

I would suspect the speedbead mount before the sight itself. You've got a plate between two parts trying to hold zero of another part that is two joints removed. It is about as easy to just send the red dot back to Burris as figure out whether it is good or not.

[WAGinVA]

How much is it off between shots?  Shotgun patterns are very variable, if it is only off several inches you may just be seeing variation from pattern to pattern.  I mounted a speed bead on a 20 gauge 391, sighted it in, killed three turkeys between 32 and 53 yards with three shots.  I have not shot it since to recheck zero.  I have read a lot of folks complain that this mount will not hold zero but my personal experience has been good so far.

[BBD]

Thanks guys.  Red dot would be off so far between shots that it was visible just looking down the barrel. I tried pushing, pulling and twisting on the gun without being able to make the dot move but after a shot it would be far enough off that I could see it just lining it up with front bead.

[WAGinVA]

Sorry but I do not understand.  When I sighted my gun in using the speed bead mount the red dot is visible just above an slightly to the right of the bead.  The speed bead mount sets the FF3 so low that you should see the bead on the front of the barrel in the scope unless your POI is way off compared to the POA using only the bead.  If you sight the gun in and shoot a target and are satisfied that the red dot is in the middle of the pattern, then shoot another target does the center of the pattern move a considerable distance?  I am not trying to argue at all, just help.

[SumToy]

 

One thing to think about is are you holding the gun the same.  I know one has a line on back the other has two lines (Burris and Venom)  cant remember.  Looks like old age is hitting me.

Line the dot in sight up the same with the back and try few cheap bird loads at 50 to 60 feet.  See if that helps then move out and try the big loads. 

I build target guns and we work alot on trying to keep them from moving around.  It is a shot gun and it will move around some but you should be able to put the 10 inch on a bird head every shot. 

One think also is if you over choke a gun it will move around also. 

[turkeyinstrut]

Something is definitely not right, I put a Speed Bead mount on my M2 20 ga. this season and between patterning and killing birds I put about 40 rounds of 1 5/8 TSS loads through it and it has never lost zero, did you make sure you tightened the little allen screw under the FF III?

[BBD]

One thing to think about is are you holding the gun the same.  I know one has a line on back the other has two lines (Burris and Venom)  cant remember.  Looks like old age is hitting me.

Line the dot in sight up the same with the back and try few cheap bird loads at 50 to 60 feet.  See if that helps then move out and try the big loads. 

I build target guns and we work alot on trying to keep them from moving around.  It is a shot gun and it will move around some but you should be able to put the 10 inch on a bird head every shot. 

One think also is if you over choke a gun it will move around also. 

You are correct, it has a single line on the back of the sight that I can line up with the bead. I sighted it in within inches by just lining the line, bead and dot up.  Shot 8-10 7/8oz loads through it with no issues. Once I got it right where I wanted it I backed up to 40 and shot a 1-5/8 load. First shot was dead nuts on.  When I went to shoot again I could tell the dot was left of the front bead. I thought I was crazy and shot it anyway.  Sure enough it hit right and low.  I have ruled everything out except the sight itself.  It's on it's way back to Burris.

[243kid]

I had issues with a speed bead and FFlll not holding zero on my Versa Max. I was using 3 1\2 #4 Long Beards. It seemed like l was always chasing the pattern and l was shooting off a bench. If l continue to use the FFIII I will use a weaver scope rail and try that?