I have a March 8-80 scope that I have been working with for about 6 months. I have been tracking the temperature shift while ranging. It seems that the temperature shift is continuous rather than a sudden shift at a given temperature. I would be interested in knowing if anyone has noticed any specific shift points or if your observations also show a continuous shift. Thanks in advance, Dennis.
March 8-80 scope temperature shift question
- Thread starter dennisu
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I would think the gun would be the culprit on poi shift here not the scope, do you have a different scope you can use to test and see if you get the same results?
John C
John C
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John, not getting a POI shift; rather ranging a target at known range at different temperatures and getting a different reading on my sidewheel. For example, when I range a 55 yard target at 80 degrees it reads 55 on my sidewheel. Not surprising since I calibrated the sidewheel around that temperature. When I range the same target at 90 degrees it ranges closer about 53 yards on my sidewheel. When I range the same target at 70 degrees it ranges closer to 57 yards on my sidewheel. Shift is similar at different ranges. Higher temperature, closer range. Lower temperature, greater range.
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Dennis, I think you just need to spend time and map it out for all temperatures you can.
According from Paul Pourch from this article he did not notice shift in his March 8-80
According from Paul Pourch from this article he did not notice shift in his March 8-80
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That’s what I have been doing. Seems pretty consistent so far. Just wondering what other shooters experience had been with the scope. Thanks for the link to Paul’s article. Good information.
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I have a Schmidt and Bender 1st generation scope that earned a bad reputation of temperature shift. Mfg says the newer model does not.
My solution was to buy a adjustable pointer that allows you to calibrate the sidewheel markings for current temperatures. A UK company made mine specifically for the S and B 10-50. It works perfectly. They make a large selection of pointers. The website is Maestro. Products are 3D printed.
This is an option for you to consider. It works foe me.
My solution was to buy a adjustable pointer that allows you to calibrate the sidewheel markings for current temperatures. A UK company made mine specifically for the S and B 10-50. It works perfectly. They make a large selection of pointers. The website is Maestro. Products are 3D printed.
This is an option for you to consider. It works foe me.
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Dennisu,
I don't know if they are on these forums, but Greg Sauve, and Al Otter have this scope on their rigs respectively. Greg has his on a Thomas carbine, at 12 ft Lbs. Al has his on his trusty USFT at 20 ft Lbs. I've shot with both of them in the past, and both acknowledge there is a temperature shift. I'm not sure if its gradual through the whole range, or if it starts at a certain temperature. Whatever the case is, even if it's different for both of them, they both agree and admit it's very consistent and predictable.
Tom Holland
Field Target Tech
I don't know if they are on these forums, but Greg Sauve, and Al Otter have this scope on their rigs respectively. Greg has his on a Thomas carbine, at 12 ft Lbs. Al has his on his trusty USFT at 20 ft Lbs. I've shot with both of them in the past, and both acknowledge there is a temperature shift. I'm not sure if its gradual through the whole range, or if it starts at a certain temperature. Whatever the case is, even if it's different for both of them, they both agree and admit it's very consistent and predictable.
Tom Holland
Field Target Tech
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I’ve shot with the 8-80 for 9 years, here’s my experience; Below 40 it ranges about a quarter inch ( on my 4.5 inch wheel) long. Above 80 it ranges about that much short. However, since cold air is denser and will lower your POI, and hot air is thinner and will raise your POI, the whole thing is pretty close to self correcting.
If your scope says 45 yards, you click for 45 yards and you hit your target, it don’t matter none if the target was actually 40 yards or 50 yards.
the March shifts in the opposite direction of most scopes. My Nikko will range short when cold, and the POI drops due to thick air, a double whammy. With the Nikko I remember starting a match at about 40 degrees. I had to add 12 clicks. As the day warmed I went to adding 10, 8, 6, etc until it got back to zero.
I advise ranging in various temps, and shoot using the range the scope says regardless if you know it to be long or short. Note where your POI is, If you are hitting your target you are good! If you need to adjust note how much and keep a compensation chart. I don’t use one.
learn your equipment and adjust.
Greg
If your scope says 45 yards, you click for 45 yards and you hit your target, it don’t matter none if the target was actually 40 yards or 50 yards.
the March shifts in the opposite direction of most scopes. My Nikko will range short when cold, and the POI drops due to thick air, a double whammy. With the Nikko I remember starting a match at about 40 degrees. I had to add 12 clicks. As the day warmed I went to adding 10, 8, 6, etc until it got back to zero.
I advise ranging in various temps, and shoot using the range the scope says regardless if you know it to be long or short. Note where your POI is, If you are hitting your target you are good! If you need to adjust note how much and keep a compensation chart. I don’t use one.
learn your equipment and adjust.
Greg
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Greg, thanks for sharing your 9 year experience with the scope. I’m continuing to test the scope as the temperature drops and it seems to line up with your comments so far. I’m having very little if any POI shift due to temperature so I have developed a compensation chart that I’m continuing to test/validate. Seems to be working out so far.
Dennis
Dennis
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