Help on FF 3 shooting low

[ahfox16]

Just had two of my shotguns (Nova and Remington 20 gauges) drilled and tapped utilizing the Sumtoy Mount coupled with my Burris FF3.  Took them to the range yesterday to get them sighted in and I don't have enough adjustment on either to hunt with.  Both shoot low utilizing all my adjustments on the FF3.  About 6" low at 40 yards.   Any ideas folks? 

PS.  Drilling and taping was done by a gunsmith who builds 1000 yard benchrest rifles.  He knows what he is doing for sure and charges accordingly.

Double PS.  I had one of the Burris FF3 on my Nova using a weaver base and the factory Burris mount, but decided it was too high and thus went the Sumtoy base route.  It did not shoot low with the Weaver base as I had enough adjustment to center the pattern. 

[tnanh]

Just had the same problem on my nephews gun. Thinking about putting my ff3 protector from gobbler 74 on that gun. I think it will lift it up some to give it a little adjustment or fix the low problem but im not sure. Hopefully someone else will chime in and let us both know.

[Fl strutter]

Try running the elevation adjustment all the way up and down 2 or 3 times and try to zero again. Its a common problem with ff3 and vortex venoms. Both companies will tell you to try the same thing to fix it. If that doesnt work may have to shim front of ff3. I had to do this once on a buddies 870. Cut small pieces of a aluminum can and placed between mount and ff3. Use however many is needed to get sighted in.

[Rapscallion Vermilion]

Try running the elevation adjustment all the way up and down 2 or 3 times and try to zero again. Its a common problem with ff3 and vortex venoms. Both companies will tell you to try the same thing to fix it. If that doesnt work may have to shim front of ff3. I had to do this once on a buddies 870. Cut small pieces of a aluminum can and placed between mount and ff3. Use however many is needed to get sighted in.

Good advice on running the adjustment back and forth.  He's shooting low, so would want to shim the back if needed.

[Fl strutter]

Yep see that now.

[ahfox16]

Thanks guys.  I'll try both.   This is sorta nuts.  I've got over $700 dollars combined in hardware (two FF3, two Sumtoy Mounts, drilling and tapping) and I can't hunt with either gun. Kinda  makes my head explode.

[CrustyRusty]

https://www.mountsplus.com/um-tactical-delrin-shim-vortex-venom-burris-fastfire.html

[turkey_slayer]

Get the shim above.  I've had to shim 2 guns.  It's tapered so you can use it to raise or lower

[ahfox16]

I'll look at the shim link.  The good news, is one of the FF3 turned out to work after I dialed the elevation dial up and down about 5 times.  It shoots fine now.  The other one that didn't work and I cut a shim from a soda can and put it in the rear and it took care of the problem.  Above said, I'll look into the shim mentioned.  Sounds like that is a better long term solution.

[SumToy]

We have did some mounts with a taper in them for guns that shoot way high or way low.  Most time the single shot stuff.       We may try one like that. 

[ahfox16]

Ordered the shim.  Long term its a better solution then a cut soda can.