Zeroing a red dot

[Sisco]

I bought a Simmons red dot for my 22/45, mounted it with a Weigand Combat mount.
Took it to the range this after noon and couldn't get it zeroed. I set the target up at 25 yards, wasn't even on the paper so I moved in to 12 yds or so.
Impact was at the very bottom of the target (standard NRA 25yd slowfire). Moved the up adjustment a few notches, still at the bottom. Few more notches, no change. Cranked the up adjustment several turns, still at the bottom. Took it so far up I thought it was going to come off the scope, no change.
Whadda ya think, something wrong with the scope?

 

[444]

Could be that there is something wrong with the sight. You don't mention if the adjustments were moving the impact higher (although still low) or the point of impact stayed in the same place dispite the adjustments.

If the point of impact was low, but the POI was moving up just not enough, I would say that the scope is not mounted in line with the bore.

 

[Sisco]

POI was pretty constant, down at the bottom of the paper.

 

[444]

Well, if the adjustments weren't moving the POI, then I would have to say there is something wrong with the sight itself.


I have had the problem of having the POI off paper and I couldn't get it on paper. But when I adjusted the scope the POI did move; just not enough. This was a mounting problem.

 

[caz223]

Place a mark at the top of the target.
Shoot at that mark.
That's your starting point.
Now adjust your sight up (Sounds like you did already.)
Just for kicks, (In case the sight is mis-marked) adjust the sight the other way a few turns.
See if it improves.
If it doesnt move, take back the sight, get your money back.
If it moves down, or up but not enough, follow directions below for shimming the mount.

First, take the sight off, and verify it's on the mount properly.
Then take off the mount and make sure it's properly on the gun, then see the mount sits flat on the gun or is hitting something on the rear of the gun.
If the mount is symmetrical, try flipping it front to back, and see if it helps.
If it has a definate front and back and if it isn't hitting anything (Piece of dirt, burr, etc.), see if there's a way to shim up the front mounting screw for the mount.
See if you can find a very thin washer that will work.
If you can't find a washer thin enough, try cutting a piece out of a coke can that matches the size of the mount. (Front screw only.)
Punch a hole through the shim where the front mounting screw is.
Try that.

 

[larryw]

I think caz223 hit that right on: assuming the dot is working, it sounds like the mount isn't square. I had the same problem (6" low at 25 yards with scope cranked all the way up) with a Weigand mount for my 10/22: soda can shim fixed that.

 

[Kruzr]

Before you shoot it, bore sight it. The Mark2 and 22/45 are some of the easiest pistols to boresight. Just take the bolt out and sight down the bore. Then adjust the dot to that point. This should get you close. If you can't get the dot there, it is a sight or mount problem. BTW, I found that one click is about 1/4 MOA so you need to move the knob quite a few clicks to get "inches" of movement.

 

[Graystar]

Do the instructions tell you how much movement to expect per click? Movement at 12 yrds might be barely noticeable.

I'd agree with 444. If you're hitting the bottom of the target at 12 yrds, there's a mounting problem.

Despite claims, red-dots can have parallax problems so it's nice to get the sight as perfectly aligned as possible before going to the adjustments.

 

[Sisco]

Pulled the sight off and re-mounted it, that may have been part of the problem. Just got back from the range, dead on zero at 25yards.

caz223 is on to something, the "Up" & "Right" arrows seem to be backwards, adjusting Up moves POI down. Thay may have been the problem yesterday too. I had the darn thing screwed so far in the up direction it was about to come out. POI probably stayed at the bottom of the target because it was screwed so far out further adjustment wasn't affecting anything.
Thanks for all the replies!