An Experience and a Question: Barrels and Ballistics
Here's a big something that some of you surely know, but for those--like me--who hadn't experienced the following consistent paradigm:
In developing loads and sighting in my newly constructed Edge I couldn't help but notice how tight the objective lens cover was; it was nearly impossible to open and closing required a "hand heel hit." Probably harmless enough to the Premier 5-25x56 it protected, but fodder for some pessimism... I first removed the whole thing and sanded down the bottom; still too tight. So, when the sun reminded me how important a sunshade could be--by sending me home as I couldn't use the scope at all--I removed the offending cover.
Upon returning to the range later in the day my dime-sized groups (100 yards) disappeared--right off the target box--investigation showed I was now impacting 18" higher than previously. Which in turn explained how I was able to sight in at 100 yards in the first place. With 20MOA in the base and 20MOA in the rings there's no way a hundred yard zero is possible. We're talking a 30" Hart BR1000 barrel--over a inch where the scope pressured it--was it the scope or the barrel that most influenced the shift in POI? I cranked the turret all the way to bottom. Still too high. yesterday, without any further adjustment I was right on at 300 yards. Too easy.
With my chronograph on strike I have no way to learn my velocity, but my loads were 94 gr. of H1000/300 Berger OTM/Nosler brass at 3.810. Anyone care to offer their experience with a similar scenario?