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Posted: 4/23/2026 8:24:18 AM EDT
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I need some insight from professionals who have experience with the inner workings of micro red dot sights. I have a Holosun 403R I was trying to zero the other day. It wasn't on paper so I thought I'd try and mechanically center the dot and start over. I turned the elevation turret all the way "up" until I hit a hard stop and then started turning it "down", counting clicks along the way. I was using the turret cap with the built in tool to turn the turret and noticed it was more difficult to turn in the down direction compared to the up direction. When I got to about 150 clicks, it was hurting my fingers so I switched to a small screw driver to continue. I used only finger pressure to turn the turret. At no point did I use the screw drive to forcing the turret. Just light finger pressure. I got somewhere between 350 and 400 clicks when I started to wonder why I wasnt hitting a hard stop point in the down direction. At that point, I looked up the full range of adjustment for the optic and found sources indicating this model has 100 MOA of total adjustment. Each click on the 403R is 0.5 MOA so that should calculate to 200 clicks of total adjustment. Realizing I had gone over, I tried to use the turret cap to turn the turret in the "up" direction (since turning the turret in that direction had always been easy with the built in cap tool). It wouldn't turn. I used the screw driver to get it moving for about 30-40 clicks, at which time the turret would turn again using the turret cap tool. At that point, the clicks on the turret returned to "normal" (it was still more difficult to turn in the down direction vs. up but that was the case from the beginning). Ultimately I was able to zero the optic. I did some more research and found red dots don't have stop points like traditional scopes and that the adjustment turrets push against a spring loaded emitter tube to move the dot. My question is, how badly did potentially I mess up this optic? How capable are they of being adjusted that far outside of their operational range? Should it be junked at this point? If you've ever been inside one of these and understand how they work, I'd appreciate your input. |
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So if I understand correctly: you adjusted it way too far in one direction, but you were able to adjust in the opposite direction. The turrets click and feel about the same as they did before adjusting too far. You were able to zero the optic and so far it's held zero. Personally I would take it out for a 'hard' range day, shooting a few mags, be a little rough with it (don't do a drop test or anything, but don't baby it), and see if it holds zero. If it does, I wouldn't worry about it. The only negative impact this could have is not holding zero, and it's pretty unlikely that you broke something that isn't immediately visible. What i'm guessing is that the adjustment is simply a thread, and you simply adjusted it so much that it unthreaded itself from the internal housing to the point where its just spinning in place (i.e. imagine when you're unthreading a bolt, and whenever it's completely clear of the threads you keep turning. No damage done, it's just skipping along the threads) |
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Originally Posted By dblazevich: So if I understand correctly: you adjusted it way too far in one direction, but you were able to adjust in the opposite direction. The turrets click and feel about the same as they did before adjusting too far. You were able to zero the optic and so far it's held zero. Personally I would take it out for a 'hard' range day, shooting a few mags, be a little rough with it (don't do a drop test or anything, but don't baby it), and see if it holds zero. If it does, I wouldn't worry about it. The only negative impact this could have is not holding zero, and it's pretty unlikely that you broke something that isn't immediately visible. What i'm guessing is that the adjustment is simply a thread, and you simply adjusted it so much that it unthreaded itself from the internal housing to the point where its just spinning in place (i.e. imagine when you're unthreading a bolt, and whenever it's completely clear of the threads you keep turning. No damage done, it's just skipping along the threads) You understand the situation correctly and I agree adjusting too far for "down" could cause the turret screw to unthread since your basically backing it out. I'm still confused myself on why it was harder to turn the turret when adjusting down vs. up. The elevation turret is on top of the optic. It has a screw that pushes against the emitter tube. There is also a spring on the opposite side of the emitter tube that provides counter pressure to the turret screw. Screwing the turret in, pushes the emitter tube downward and compresses the opposing spring. Unscrewing the turret relieves tension on the emitter tube and the opposing spring pushes the tube back upward. Now, to move POI down, the dot has to move up. This would mean unscrewing the turret screw, which relieves tension. So why is it the function that requires more force? You'd think adjusting up, where you are increasing tension on the tube and spring to push it downward, would require more force 
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Originally Posted By GlockPride: If it holds, you should be good. If not, wouldn’t Holosun warranty help you out? I'm sure they would. It's just that they don't make the 403R anymore and I really like this optic. I like the reostat dial vs push buttons and the dot is the only dot I've seen that remains round and crisp with my astigmatism. It's quite remarkable actually how clear it is despite my crappy eyes 
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Originally Posted By Frens: Only time will tell.. but the chances it’s fine are quite high since red dot are not like prism scope like you mentioned Btw I’m amazed by your ability to patiently count up to 400 clicks Thanks - I've had to do it before to diagnose tracking issues on broken scopes to confirm they were DOA, so I have some experience with it. I'll admit I was not a portrait of patience yesterday though. |
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