Scope adjustment in cold weather
- Thread starter Fisher1
- Start date
If bullet impact changes over time, its more likely to be the rifles bedding or barrel no floated.
I can see that happening. Cold contracts, heat expands
Lets look inside a scope.
I can see that happening. Cold contracts, heat expands
Lets look inside a scope.
Coyotefurharvester
Silver $$ Contributor
Not all scope companies use the same(quality)internal lubricants.
I shoot every day it is above -18C and have a NF Comp. I would say the Sightron 36x that preceded it did not make accurate adjustments. The NF does but it has other issues in the cold. Obviously all of the various materials expand and contract at different rates and to different amounts. When we hunt the rifles are left outside the tent in winter and all is good. But my 22 rifle doesn't like the cold so it gives me about 1/2 an hour of good performance before things go south. But the scope clarity, parallax and zero have to be chased during that 1/2 hour.
I recently spent some time reading March literature and it seemed like they were saying they were doing things in their design to address just these issues. Suppose that means I need a new scope!
I recently spent some time reading March literature and it seemed like they were saying they were doing things in their design to address just these issues. Suppose that means I need a new scope!
I always do that regardless. It’s probably not usually necessary, but it can’t hurt.
jackieschmidt
Gold $$ Contributor
All scopes have an erector table with some type of pre loaded gimble joint.
I can see that joint getting a little stiff in extremely cold weather, especially if the manufacturer put some type of lubrication on the joint.
most top end scopes rely on hard anodizing at the joint, making it lubrication free.
I can see that joint getting a little stiff in extremely cold weather, especially if the manufacturer put some type of lubrication on the joint.
most top end scopes rely on hard anodizing at the joint, making it lubrication free.
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I've always heard that you should make a decision on the value of the change you want to make on the turret. Say you want to move the turret from a 2 to three. You should turn the turret to 4-5 then back to 1, then finish with a right turn back to the 3 that I wanted in the first place. I was told it minimizes the lash in the adjustment threads. Always finish adjustments with a right turn.
xswanted
Gold $$ Contributor
A number of years ago I worked for a gun/optics shop and had access to a half dozen high end scopes from the store as well as a few others borrowed from friends.
I also live in ND where it’s currently -24 below zero and of course none of our Januarys are ever very warm.
Myself and my dad decided we should test the theory that scopes do not adjust reliably in the cold as we had both experienced what we perceived as a scope tracking incorrectly when the temperature dipped below zero degrees.
So we tried keeping it as controlled as we could.
Here’s what we did.
We acquired 6 high end scopes which were all nearing $2000 at the time, which was somewhere around 2011 I believe.
I don’t recall models however we had 2 different Nightforce, a Vortex, 2 Leupolds, and a Swarovski.
We zeroed all the optics on the same rifle, a 6 Dasher, that was a proven rifle in accuracy at 100 yards.
All the scopes had rings or a mounting system that allowed them to be removed from the scope rail and reattached without any major shifts in POI.
We waited for a day that was below zero. And we ended up getting a day that was around -15F for the high.
We placed all the scopes on a gun bench outside in the early morning. Just after lunch we tested.
The rifle stayed inside our heated shop and was brought outside to shoot.
First scope was re mounted outside and we shot 2 shots then dialed the scope up 5 MOA fired 2 up 5 MOA fired 2 dialed up 5 MOA fired 2 then dialed back down 15 MOA and fired 2 final shots.
The rifle was placed back inside the shop to warm up to room temp and then we would test the next scope.
All 6 scopes were tested like this.
As soon as we hit a warmer day we did the test again. The second test was down above freezing but below 40 degrees, conducted the exact same way.
In the extreme cold none of the 6 scopes would repeat back to zero until the second shot was fired. Meaning it took a little impact to get the scope back down to zero and the original group.
Going up there was no issue. Coming down, all 6 scopes had their first shot back at zero land high above the original POI. None were more than 1” from zero but they all failed that part.
In the second test above freezing all scopes preformed as they were expected to.
I believe this to be a common trait among many optics. And when it’s very cold and I’m hunting, I always tap my scope when I click it back to zero just in case it didn’t get all the way back down internally.
Not 100% scientific but the results were consistent.
JEFFPPC
Gold $$ Contributor
What's interesting in this to me is that I have sent 3 high end scopes, 3 different makes, for the exact reason you report. This is in mostly 70 to 80 degree weather. They would click up fine 100 percent. They would almost never come back down to zero. One was sent back because the problem was not corrected. It came back and I sold it giving the buyer the history. Buyer said it worked for him but he got rid of it after a couple matches and would not give me any further information as to why.
jelenko
Gold $$ Contributor
How much was it off when clicking down?
JEFFPPC
Gold $$ Contributor
Coming from 500 yds to 100 yds it would usually be 3 to 8 clicks.
Coyotefurharvester
Silver $$ Contributor
I usually dial for shots over 250 yards in the winter when stalking fox/coyote during the day. I have a Sightron stac on my 22-250 and Leupold on my 17 rem. Both rifles have Lilja barrels and are one hole accurate. Scopes have/are retaining zero across multiple winters. I try to take shots inside 225 yards on days temps are below zero as I don't trust the mechanisms on scopes in severe cold. I have confirmed this at 300 yards a couple times in subzero temps. I also have found up is less of a problem than down, but I don't like the not returning (down) to expected zero so I don't dial. Below zero testing is not fun shooting as xswanted would probably agree with.
Coyotefurharvester
Silver $$ Contributor
Well your half way there on your cheat sheet.
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