hvsmith Posted August 4, 2012 Share Posted August 4, 2012 I can't hold zero on my C-More Quinn II mount at all.I've read & researched the topic thoroughly but obviously I'm not doing something right. I had a plastic version on it, kept zero for 4 months then went south. I'd re-zero it, would stay for a match & then go south again. I read that the aluminum model held zero more consistantly so I ordered & installed her. Red loctite the aluminum one, set up zero shooting one ragged hole & everything is good. Next practice I like to check zero at the beginning, I'm not even close to being on. Re-zero, go through 250 rounds, everything is perfect until all of a sudden I'm 8" low & 3" right - WTF! - re-zero, finish the practice, check zero & it's perfect. Clean her up, go to a match today, 1st target is a 6" plate, put my dot right in the middle, bang, nothing, bang, bang, bang, nothing, I have a beautiful group into the no shoot behind the plate 8" low - WTF! Do I pull her off & start from scratch? Does c-more sell the elevation screw that I now have buggered up? I have no idea what I'm not doing wrong & really could use some guidance & help with this real PIA before I totally lose my mind. Link to comment Share on other sites More sharing options...
Retread1911 Posted August 4, 2012 Share Posted August 4, 2012 Are you tightening the lock screws after you get them set? Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 Are you tightening the lock screws after you get them set? Yes, tight but not enough to strip the threads. Link to comment Share on other sites More sharing options...
Sarge Posted August 5, 2012 Share Posted August 5, 2012 WOW! That sucks Herb. I only know mine had a loose lock screw when mine started floating high this spring. I would say it's a bad sight but two in a row? Not likely. Do you have an upright mount to bolt it to to see if it holds? Did you try a brand new fresh battery? Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 I don't have an upright mount & I just changed my battery when I put the new c-more on - see why I'm going crazy! Link to comment Share on other sites More sharing options...
SLM Posted August 5, 2012 Share Posted August 5, 2012 You don't have a glare shield on it do you? Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 Yes I do, could that have something to do with it? Link to comment Share on other sites More sharing options...
Neomet Posted August 5, 2012 Share Posted August 5, 2012 Mark the screws and body so you can see if the screws are moving. You also might check the tightness of the screws mounting the scope to the mount and the mount to the frame. I would not recommend Red loctite. That stuff is for "I never want to take it off again" parts. Blue is better for this app in my opinion. Link to comment Share on other sites More sharing options...
SLM Posted August 5, 2012 Share Posted August 5, 2012 Yes I do, could that have something to do with it? I had one that I had a shield on and had to sight it before every match or it was off. I took the shield off and put the regular plate back on and it held zero just fine after that. I don't know why but my guess was that because the shield hits on the top of dot module temperature changes caused the plastic to shift and move the module around just a bit. I never did try it but I wondered if taking the shield off, putting a bit of soap on top of the module then reinstalling the cover would let it pull down without torquing the module? Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 Thanks Ryan, I'll give that a try. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted August 5, 2012 Share Posted August 5, 2012 Herb, I had the same problem a few years ago with my STI TruBor. After months of trying EveryThing, turns out is was the gun's grip screws were loose I loctited them, and problem hasn't recurred in three years Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 Herb, I had the same problem a few years ago with my STI TruBor. After months of trying EveryThing, turns out is was the gun's grip screws were loose I loctited them, and problem hasn't recurred in three years Thanks Jack, will do that today. Link to comment Share on other sites More sharing options...
CocoBolo Posted August 5, 2012 Share Posted August 5, 2012 Food for thought: 1. Every time you change your Load even a different lot of the same powder the Zero can and will move. I have not seen 8" but 4 or 5 yes. 2. Bullets hitting the comp. Look for small flakes of of copper jacket in the comp, and also very small lines in the flat edge of the bore holes in the comp. I periodically clean the bore holes in the comp when carbon builds up on the surfaces, a precaution. 3. Build up of crud in the comp, cleaned one up for a GM, that had been shooting RN zeros, lead and crud had built up in the small area at the end of the barrel. In that case bullets were also tumbling, at times. If the gun will shoot a nice 10 shot group then the 3 items above don't apply. I had the same issue as you, it was a cracked frame on the C-more, replaced it and no more issues. Link to comment Share on other sites More sharing options...
Neomet Posted August 5, 2012 Share Posted August 5, 2012 One other thing to possibly check is to be sure the lock screw for the windage (now your elevation screw) is actually locking down the adjustment screw. I've had two Cmores where the nose of the lockdown screw was bottoming out into the body rather than the head of it capturing the adjustment screw. Just tighten the locking screw up and see if the adjustment will still turn. Also I put a small star lockwasher under the locking screw so that it more positively captured the adjustment screw. That is what eventually cured my windage walk. Link to comment Share on other sites More sharing options...
hvsmith Posted August 5, 2012 Author Share Posted August 5, 2012 Thanks guys for your suggestions - it's OK if I completely back out the locking screw? Where can I find that small of a star lock washer? My compensator is clean as a whistle & I only shoot one load & powder so I don't think that would be my problem, but thanks for your suggestions Coco. Link to comment Share on other sites More sharing options...
RH45 Posted August 6, 2012 Share Posted August 6, 2012 There was another thread here somewhere, and one fellow had a link to a tutorial on how to put a little blue locktite on the windage adjustment, but, you have to remove the sight from the mount. One of my open guns has a Barry mount, which is a PITA to sight in anyways, that does the same thing. I've tried 2 different C-Mores, and am going to take the time to try the locktite thing. Neither C-more had a problem when they were mounted upright. Link to comment Share on other sites More sharing options...
Neomet Posted August 7, 2012 Share Posted August 7, 2012 (edited) Thanks guys for your suggestions - it's OK if I completely back out the locking screw? Where can I find that small of a star lock washer? My compensator is clean as a whistle & I only shoot one load & powder so I don't think that would be my problem, but thanks for your suggestions Coco. Yep, taking the locking screw out is no biggie. The locking star washer can be scored at Home Depot or Lowes. It is pretty small. Edited August 8, 2012 by Neomet Link to comment Share on other sites More sharing options...
R.Elliott Posted August 13, 2012 Share Posted August 13, 2012 I've fought with this same issue. Almost drove me insane. First: remove the dust shield. Certain types can let the dot module wander around and you will not be able to ever lock it down. Second: take the scope off the mount and put some blue Locktite on the windage worm. Run it back and forth a few turns and make sure the threads are coated. Reinstall the scope, sight in and it should be good to go. Link to comment Share on other sites More sharing options...
oteroman Posted December 24, 2012 Share Posted December 24, 2012 Are there replacement locking screws available to buy for the C-mores? (torx or normal flatblde screws) I just bought my first C-more and the locking screw is not tight (I can easily adjust the windage) but when I went to try and tighten the locking screw I put as much force as I felt comfortable with and it would not move??? With those small allen you don't have much leverage to begin with...Not that I am looking to apply extream force, the base is plastic and I intend to be careful. I hate to send this thing back. I was thinking of gently taking a dremel cutting wheel to the center and scoring a straight cut so a screwdriver could be used. Link to comment Share on other sites More sharing options...
Jaxshooter Posted December 24, 2012 Share Posted December 24, 2012 You can put a small washer under the lock screw . On some C-Mores the lock screw does not hold unless you put a washer under it or Loctite them. They bottom out and there is not enough tension to keep them from vibrating loose. Link to comment Share on other sites More sharing options...
Shadow Posted December 25, 2012 Share Posted December 25, 2012 hvsmith- Are you using a thumb rest? You need at least two screws holding the mount to the frame not going through the thumbrest holes or the mount can shift. Link to comment Share on other sites More sharing options...
hvsmith Posted December 25, 2012 Author Share Posted December 25, 2012 hvsmith- Are you using a thumb rest? You need at least two screws holding the mount to the frame not going through the thumbrest holes or the mount can shift. Yes I have a thumb rest on the right side of the frame, being a Lefty - there is 2 screws attached to the frame, same as used for the C-More attachment but the length of the screws is cut so they don't go through the frame. Link to comment Share on other sites More sharing options...
Sarge Posted December 25, 2012 Share Posted December 25, 2012 Herb are you still having issues? I thought you would have this figured out long ago. Link to comment Share on other sites More sharing options...
hvsmith Posted December 25, 2012 Author Share Posted December 25, 2012 Herb are you still having issues? I thought you would have this figured out long ago. I was just answering the question from Shadow about my thumb rest. No problems at all - made a trip to GA & everything was taken care of, less than a week turnaround time, a happy camper. Link to comment Share on other sites More sharing options...
Sarge Posted December 25, 2012 Share Posted December 25, 2012 For any future reference what was the culprit? Link to comment Share on other sites More sharing options...
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