JThompson Posted December 6, 2007 Share Posted December 6, 2007 (edited) I shot yesterday after having my gun and bag in the car most of the day. It was in the teens and when I shot the first targets, my gun was 4-5 high at 25yrds. I thought maybe I had banged the C-More or something. I didn't feel like moving it, so I just aimed a bit low at 25. Later I shot some plate racks and was getting some misses. I went back to paper for a head shot and found it had come back to center, so I was shooting over the plates. It seems that either the gun ammo or C-More had changed with the cold. I'm thinking the C-More because of the cold... the strange thing is that it was on center. I use the Barry mount so having it be perfect high would be strange. I did a search to see if this was covered, but the search function and I don't get along well. Anyone have this issue. This is the first time I've shot in cold weather with this gun and it has me scratching my head a little... Edited December 6, 2007 by JThompson Link to comment Share on other sites More sharing options...
BritinUSA Posted December 6, 2007 Share Posted December 6, 2007 Eric Grauffel mentions this on the IPSC Global Village. It seems he has noticed that extreme temperature variations affect the zero on the C-More. Link to Global Village post Link to comment Share on other sites More sharing options...
JThompson Posted December 6, 2007 Author Share Posted December 6, 2007 (edited) I don't have an account there... could you repost with credits? Either that or send it to me PM if you would be so kind... Thanks Edited December 6, 2007 by JThompson Link to comment Share on other sites More sharing options...
SA Friday Posted December 6, 2007 Share Posted December 6, 2007 Are you using a temp sensitive powder? Link to comment Share on other sites More sharing options...
AlamoShooter Posted December 6, 2007 Share Posted December 6, 2007 (edited) I don't know But possible if you had the gun in the bag with Presser/pushing on the c-more lenz hood = it would let the plastic "Take A Set" -In the cold and after it had a chance to warm up the plastic got flexible again. The entire sight it with a C-More depends on the flex in the front bands. But ...I don't know nothing Edited December 7, 2007 by AlamoShooter Link to comment Share on other sites More sharing options...
JThompson Posted December 6, 2007 Author Share Posted December 6, 2007 (edited) Are you using a temp sensitive powder? Silhouette... I don't know But possible if you had the gun in the bag with Presser on the c-more lenz hood = it would let the plastic "Take A Set" and after it had a chance to warm up the plastic got flexible again.The entire sight it with a C-More depends on the flex in the front bands. But ...I don't know nothing True... Edited December 6, 2007 by JThompson Link to comment Share on other sites More sharing options...
BritinUSA Posted December 6, 2007 Share Posted December 6, 2007 I don't have an account there... could you repost with credits? Either that or send it to me PM if you would be so kind... Thanks To paraphrase; If you sight the gun in at 10C(50F) it will have a different zero at 30C(86F). It probably has something to do with the plastic, a metal scope would not have that problem. Link to comment Share on other sites More sharing options...
JThompson Posted December 6, 2007 Author Share Posted December 6, 2007 I don't have an account there... could you repost with credits? Either that or send it to me PM if you would be so kind... Thanks To paraphrase; If you sight the gun in at 10C(50F) it will have a different zero at 30C(86F). It probably has something to do with the plastic, a metal scope would not have that problem. Ya. That makes sense... the gun was sighted at about 80+ so for the first while I had a variation of over 50. I'm glad I found out now rather than in a match. Thanks for the reply Link to comment Share on other sites More sharing options...
Pat Miles Posted December 7, 2007 Share Posted December 7, 2007 JT, Why don't you dial up the good folks at C-More and run your scenario past them? CYa, Pat Link to comment Share on other sites More sharing options...
dajarrel Posted December 7, 2007 Share Posted December 7, 2007 Just an uneducated thought, but could it be effect of a cold bore on the handgun rather than the C-More? Perhaps even a combination of the two. Just askin' dj Link to comment Share on other sites More sharing options...
Dan Sierpina Posted December 7, 2007 Share Posted December 7, 2007 Molded plastics are loaded with stresses. The cold temperatures will make the plastic do weird things. Link to comment Share on other sites More sharing options...
JThompson Posted December 7, 2007 Author Share Posted December 7, 2007 (edited) Double Edited December 7, 2007 by JThompson Link to comment Share on other sites More sharing options...
JThompson Posted December 7, 2007 Author Share Posted December 7, 2007 It could be any number of things... I don't see a good way to figure out what factors are at play here. The only positive way I can thing of is to ransom rest the gun at room temp and then bring it down below freezing. If it's still shooting on center I can rule out ammo, gun and I'll it's C-More. There is another possibility here. My "Barry Mount" is aluminum and supported on one side. The mount might be moving with the cold as well. The above test will tell me if it's either of these. I don't have a ransom, so it's moot right now. The best I can think to do is bore sight the thing on a sand bag at regular and cold and see if that changes. Not an optimum answer for sure.... I'm open for suggestions from you guys... Jim We have a winter match coming up and I'd like to have some way to test this out before then. I will contact C-More as suggested too. Link to comment Share on other sites More sharing options...
lcs Posted December 7, 2007 Share Posted December 7, 2007 It could be any number of things... I don't see a good way to figure out what factors are at play here. The only positive way I can thing of is to ransom rest the gun at room temp and then bring it down below freezing. If it's still shooting on center I can rule out ammo, gun and I'll it's C-More. There is another possibility here. My "Barry Mount" is aluminum and supported on one side. The mount might be moving with the cold as well. The above test will tell me if it's either of these. I don't have a ransom, so it's moot right now. The best I can think to do is bore sight the thing on a sand bag at regular and cold and see if that changes. Not an optimum answer for sure....I'm open for suggestions from you guys... Jim We have a winter match coming up and I'd like to have some way to test this out before then. I will contact C-More as suggested too. Not that this is a suggestion, more of an observation. We shoot indoors ( might as well be outside) and the temp can be in the low 30s inside during Jan-Feb and I have never experienced any sight deviation close to that. Having said that, I pick up my gun from home and it is a twenty minute drive to the range with the gun in the trunk. So I would presume the C-more was pretty dang cold by arrival time. May be not cold enough to affect zero alignment though. Link to comment Share on other sites More sharing options...
JThompson Posted December 7, 2007 Author Share Posted December 7, 2007 It could be any number of things... I don't see a good way to figure out what factors are at play here. The only positive way I can thing of is to ransom rest the gun at room temp and then bring it down below freezing. If it's still shooting on center I can rule out ammo, gun and I'll it's C-More. There is another possibility here. My "Barry Mount" is aluminum and supported on one side. The mount might be moving with the cold as well. The above test will tell me if it's either of these. I don't have a ransom, so it's moot right now. The best I can think to do is bore sight the thing on a sand bag at regular and cold and see if that changes. Not an optimum answer for sure....I'm open for suggestions from you guys... Jim We have a winter match coming up and I'd like to have some way to test this out before then. I will contact C-More as suggested too. Not that this is a suggestion, more of an observation. We shoot indoors ( might as well be outside) and the temp can be in the low 30s inside during Jan-Feb and I have never experienced any sight deviation close to that. Having said that, I pick up my gun from home and it is a twenty minute drive to the range with the gun in the trunk. So I would presume the C-more was pretty dang cold by arrival time. May be not cold enough to affect zero alignment though. Interesting... I think I will keep the ammo warm and let the gun get cold for my first attempt at isolating the problem. Link to comment Share on other sites More sharing options...
Front Man Posted December 7, 2007 Share Posted December 7, 2007 My CMORE won't stay zeroed regaurdless of the temperature. Every night before a match this year I would bench shoot about a hundred rounds to rezero. (No, nothing is loose.) FM Link to comment Share on other sites More sharing options...
JThompson Posted December 7, 2007 Author Share Posted December 7, 2007 My CMORE won't stay zeroed regaurdless of the temperature.Every night before a match this year I would bench shoot about a hundred rounds to rezero. (No, nothing is loose.) FM Send it back.... they are good people and will get it fixed up for you. Mine holds fine, I just have a cold issue. Jim Link to comment Share on other sites More sharing options...
SA Friday Posted December 7, 2007 Share Posted December 7, 2007 JT, why would the POI change perfectly verticle? I have some doubt's it would be the C-More that is doing this because of the way it's mounted to the gun. The only way the dot would be off exactly straight up is if the C-More warped at that exact angle. Out of 360 degrees to warp, it warped exactly in a straight up direction? What are you using for gun lube? Did it solidify because it was cold and that changed the impact point? And then after the gun warmed up it went back to it's original 'warm' zero? Link to comment Share on other sites More sharing options...
MichiganShootist Posted December 7, 2007 Share Posted December 7, 2007 When I saw this thread......... Cold & High......... I thought it was about my exwife Link to comment Share on other sites More sharing options...
BritinUSA Posted December 7, 2007 Share Posted December 7, 2007 JT, why would the POI change perfectly verticle? I have some doubt's it would be the C-More that is doing this because of the way it's mounted to the gun. The only way the dot would be off exactly straight up is if the C-More warped at that exact angle. Out of 360 degrees to warp, it warped exactly in a straight up direction?What are you using for gun lube? Did it solidify because it was cold and that changed the impact point? And then after the gun warmed up it went back to it's original 'warm' zero? The height adjustment screw prevents it moving left and right. I think the problem is the way that the scope legs bend over, there is tension there and that could get affected by the cold. Link to comment Share on other sites More sharing options...
JThompson Posted December 8, 2007 Author Share Posted December 8, 2007 I'll let you guys know if/when I get it figured out. Link to comment Share on other sites More sharing options...
G-ManBart Posted December 8, 2007 Share Posted December 8, 2007 I'll let you guys know if/when I get it figured out. JT, I'm sort of a knuckle dragger when it comes to fixing things....simple is good! The first thing I would do before getting too wound up would be to let the gun and ammo cold soak to around where it was when you noticed the problem and then run a few over the chrono. If you get the same figures, or close, to what you normally get then you've eliminated one variable immediately. I'm not familiar with your mount, but keep in mind that different metals expand/contract at different rates (I'm sure you know this) and that could be causing a push or pull somewhere that isn't seen at warmer temps. I'd think that the plastic/polymer of the C-More wouldn't change much with temperature....if that wasn't the case I'd expect to see tons of problems with polymer-framed guns due to temperature issues...slide rails binding on the inserts etc, and that doesn't really happen. Sure will be interesting to hear what you figure out! R, Link to comment Share on other sites More sharing options...
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