Help with sighting in

[roosterstraw]

At 20 yards I'm shooting right on but if I move out to farther distance it's low but the problem is my reflex sight is maxed out on the elevation. Any help would be appreciated.

Mossberg 500
12 gauge
Carlson .660
3" lonbeard
3" federal tss 9 shot
Holosun 507c
Sumtoy base

[Tom007]

Contact Willam at SumToy, he will have an answer...

[roosterstraw]

Shot him an email.

[PV266]

Can you shim the base?  Cut a small piece of aluminum from a can and put it between the sight and base. I don't know the footprint of the sight, but there used to be pre made shims on Amazon for fastfires.

Ade Advanced Optics Optics Delrin Shims 1.0 Degree for Vortex Venom & Viper, Burris Fastfire II, III,Red dot Sight

[roosterstraw]

Can you shim the base?  Cut a small piece of aluminum from a can and put it between the sight and base. I don't know the footprint of the sight, but there used to be pre made shims on Amazon for fastfires.

I'f I brought the sight up that would make me shoot even lower wouldn't it? Or am I thinking about it wrong.

[roosterstraw]

Can you shim the base?  Cut a small piece of aluminum from a can and put it between the sight and base. I don't know the footprint of the sight, but there used to be pre made shims on Amazon for fastfires.

I'f I brought the sight up that would make me shoot even lower wouldn't it? Or am I thinking about it wrong.

You're right. I needs to be shimmed up.

[PV266]

The Delrin ones have a built in angle to them. Higher in the back than front. Hope it works out for you...

[roosterstraw]

Is it normal to have to shim or do I have something else going on.

[PV266]

I can't speak to the holosun I've never owned one but it is somewhat common with the Fastfires.  Common enough that the shims are sold on Amazon.

[roosterstraw]

Ordered a shim from ade. They responded to my email and shipped it out all within a couple hours. Great customer service for sure.

[roosterstraw]

Anyone else had this issue with a Holosun?

[jhoward11]

I shimmed and then j-b weld in place. No adjusting after that, but it worked for my 500

[sixbird]

Shim the back of the base. That'll solve your issue. You can get shims from vortex or on the net.
The other thing to try, although it hasn't worked for me, is to run the adjustments up and down until they bottom out. Vortex claims that fixes some of them. I'd guess Holosun would be similar.
The shim under the rear of sight will absolutely fix your issue though.

[JeffC]

Anyone else had this issue with a Holosun?

have same site, no problems adjusting height or left/ right, but only took minimal adjustment to be dead on.

[roosterstraw]

Anyone else had this issue with a Holosun?

have same site, no problems adjusting height or left/ right, but only took minimal adjustment to be dead on.

They said I could send it back to be looked at but it probably won't be back in time for the start of season.