effects of cold weather

mikeystew

mikeystew

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i have a rather cheap scope on a 30-30 that has worked flawlessly for 5 months or so shooting it every week. never lost it's zero. but today my first shot was high left, i thought wtf... adjusted it and it fired 2 shots just below bullseye... ok! next series of 3 shots grouped slightly high right. from then on, 8 shots or so were dancing all around the bullseye when aiming at the same spot.
i do not know the mechanics of how a scope works, but would the fact that this is the first time i've used it in near zero temperatures account for the wild shots? i know it's not the gun, and the mounts are tight and locktited on there so the unit was good and stiff. but why now would it no longer hold zero?
any thoughts or opinions are more than welcome.
 
Or the cold weather has affected your stock and its touching the barrel. Had that happen to me years ago on a M77 Ruger...scope was just fine it was the weather!
 
Hahahaha! i F'n knew that would be the first answer! lol... well, it's a 336 marlin and i've done a thermal sillicone bedding job on the forestock, so i figure it's the scope. what im trying to do is learn a little something about scopes here. without a winded explaination does anyone know if the cold could have anything to do with it or not?
while writing this i looked over it a little more, and noticed that the objective lens moves about 5 degrees around when i turn the front focus knob either way. i assume that would do it. piece of chit! i need a better paying job dammit! could anyone recommend a decent scope for $200 - $300
 
mikeystew said:
i have a rather cheap scope on a 30-30 that has worked flawlessly for 5 months or so shooting it every week. never lost it's zero. but today my first shot was high left, i thought wtf... adjusted it and it fired 2 shots just below bullseye... ok! next series of 3 shots grouped slightly high right. from then on, 8 shots or so were dancing all around the bullseye when aiming at the same spot.
i do not know the mechanics of how a scope works, but would the fact that this is the first time i've used it in near zero temperatures account for the wild shots? i know it's not the gun, and the mounts are tight and locktited on there so the unit was good and stiff. but why now would it no longer hold zero?
any thoughts or opinions are more than welcome.
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It could be a variety of things, different ammo, ? is your barrel clean? different barrel temp?

I'd venture you are using different ammo which can make a HUGE difference in some guns
 
The ammo could be shooting to a slower velocity, causing the groups to open up a bit and the POI to change.

Either that or you have a crap scope :D

I would recommend the Bushnell 3200, Vortex Diamondback or the Burris FFII, all of which are fantastic scopes within your price range.
 
yeah... same ammo, lot#, clean bore. unfortunately i ran out of ammo before i could test it with the irons, but i think the scope has got a loose lens. im looking for a 30 to 40 reticle variable power (3-7x), but id settle for anything really as long as it's durable and i can see the deer in low light...
 
The cold temperature can cause your ammo to shoot significantly slower than it does in warmer weather, even using the same ammo lot.

I don't think you could go wrong with any of the 3 scopes I listed above, with the Burris FFII 3-9x40 probably being the brightest of the three when the sun starts going down.
 
Well - I went through this a few years ago. In cold weather, I had several scopes "walk" after attempting adjustments when cold. This included both cheap scopes and fairly good ones (eg 3200's)
 
Cheap scopes don't use very good adhesives on the lenses so lens walking may be the cause, adjustment knobs may very well be the culprit moving everytime the trigger is pulled as they don't lock well, not all materials used in cheap scopes are going to shrink at the same rate in cold weather, so its beginning to look like you may want to send it back if its under warranty or spend a little more. the burris and bushnell elites are getting good reviews, millet is too.
 
and noticed that the objective lens moves about 5 degrees around when i turn the front focus knob either way. i assume that would do it. piece of chit
Click to expand...
mikeystew ... could you expand on that comment -- are you using a scope with parallax adjustment on a 30/30? Just curious. I think if you stick to a fixed 4x (2 1/2 or 3x even better) scope you may find a good used one in your price range. Fixed scopes are generally lighter (handier on a brush rifle) and have less to go wrong. If you can shoot consistent 3 shots groups in 4 inches (same mpi) at 100yds with a 30/30 - out of a cold barrel - thats a pretty good deer rifle imo - if you can do that standing - thats great!
 
Suspect the ammo first. Lenses don't "walk", but temperature can affect the ammo. Like Levi says, shooting without the scope will tell you.
 
sunray said:
Suspect the ammo first. Lenses don't "walk", but temperature can affect the ammo. Like Levi says, shooting without the scope will tell you.
Click to expand...

mounting the scope on a rimfire, and shooting a box/square will tell you much about the scope.
Then the ammo can be tested the same way in another gun, or use some factory ammo to confirm all good.
Then its on to the bases, and making sure their not moving...etc
 
Sunray - I can assure you that the adjustment mechanisms on scopes can cause shots to "walk" after an adjustment in very cold weather. Have you ever seen people tap the scope tubes while making adjustments?
Regardless, as mentioned above, shooting the rifle with iron sights is the "acid test".
 
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