Quote:
Originally Posted by BigJon
If I had a zero shift like that from warm to cold temperature shooting I would have some concerns about a mechanical issue with rifle/scope/mounts.
I shoot year round and have not seen a shift like that even when using temperature sensitive powders that show a considerable velocity drop from warm to cold temps.
Looks like it groups well after you made an adjustment but I would be seeking a culprit to fix to achieve consistency.
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At this point, I am not sure that it is a shift caused by a temperature change. The rifle was sighted in three years ago, and I never fired the rifle the past two years, since I didn't hunt big game for two years. But I will be doing some testing next spring to see if this really is a case of temperature effecting the rifle or the ammunition, or whether something occurred during the past three years that may have effected the zero. I did sight in at 200m yesterday, vs 200 yards initially, but 20 yards should only make a difference of about 3/4", which still leaves a difference of about 2-1/2". The only other thing that has me wondering, is that the vertical adjuster was not set to zero , and I usually do set them to zero after doing a sight in. The adjusters do pull out to zero , but now I am wondering if the calibrated rim was not fully pushed back in and tightening the cap may have turned it. The direction of rotation is correct to lower the point of impact. It doesn't seen likely, but until I shoot in warm weather again, I have no better explanation.