Temperature?

22 Long Rifle ammo is finicky. Tell us all about it here.
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steel_ram
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Temperature?

Post by steel_ram »

I know it;s been touched on in other threads but, what effect does temperature have on smallbore ammo, particularly at 100 m's?

Would this account for strange big misses on a cold day?

What adjustments do you pro's make for temperature, rain and other atmospheric conditions?
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Post by Joaquin B »

Based on experience, the best thing you can do for shooting in cold temperatures is to have some Lapua Biathlon ammo on hand. I think the priming compound, powder and lubricant are designed to operate better at low temperatures.

I learned about this after shooting a couple of "frozen finger" matches in January of 2002 and 2003 in Wisconsin. The temperatures were a balmy 5 and 8 degrees F. and I discovered that the treacherous Wisconsin old geezers were using this ammo and scoring hits consistently, while the inexperienced warm-blooded types among us (me) were spraying the range (shivering also had an effect) and only scoring with the first 1 or 2 bullets we could pull out of our pockets with frozen fingers. :)
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Post by ajj »

Cold temps are generally assumed to degrade the accuracy of .22 rimfire ammo. There are many variables (temp, ammo, gun are the three big ones.) Under 50 F can be "too cold" for some ammos according to some BR shooters. Explanations vary from effect on the lube to the cold barrel robbing too much heat from the small volume of propellant gas. But "...they just don't shoot as well in the cold..." has been my experience. There is no point in trying to test ammo lots in cold weather. http://www.benchrest.com/forums/showthread.php?t=39293
I'd be interested in what people have to say about atmospheric conditions.
I read a very interesting article years ago about the effect of rain on 100 yd centerfire benchrest shooting. The most interesting thing to me was that the chances of the bullet hitting a raindrop, even in a heavy downpour, are quite small. When that does happen there may or may not be some, small deflection. But the only advice is to forget about rain. Except to get in out of it.
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Jason
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Post by Jason »

The short answer to your question is that it depends on the ammo. The most sensitive ammo to colder temperatures that I've personally experienced is Wolf/SK. I've had them shoot about 3/4 a minute lower when I zero my elevation knob for chickens and had another 3/4 a minute or so that I had to add on top of that compared to my normal adjustment from chickens to rams. This is going from a high-50s to low-60s degree zero to high-20s to low-30s temps. I was determined to fight the ammo that I had tooth and nail to find one that shot well in cold weather this past year, and I finally did. The 2+ year old lots of Golden Eagle Target did well in the cold as far as accuracy and only lost a little velocity, resulting in slightly different scope settings. Unfortunately, I don't have any more of it and can't find any more. I haven't had the new lot that I recently got a case of long enough to test it in the cold, but my initial impressions of its accuracy even at 45 degrees or so aren't good enough to care how it shoots in cold weather.

Next year, I'll be buying a brick or two Eley Biathlon and not having quite as many headaches and wasted range sessions. :)
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Post by ajj »

Sorry if I was too wordy. It's just the way I am.
Don't buy too much Biathlon if you can't test lots. My rifle didn't like it.
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Jason
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Post by Jason »

I wasn't implying that your answer was too long. I was trying to keep my own answer shorter than normal, as I tend to get long-winded when it comes to shooting topics. :)
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temprature

Post by Jerry G »

You can cook your ammo if you don't watch it in the summer. Keep it out of the direct sunlight as much as you can. I think it is a good idea to keep it in a small cooler in the summer and keep it in the shade.
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Post by ajj »

[quote="Jason"]I wasn't implying..."
No, no, I actually read my post and realized it didn't say much.
Biathlon ammo is worth a try for all temperatures if you can stock up on a good lot. Just hasn't worked for me yet. I think the Biathlon formula is a wee tad more velocity and lighter, or less lube.
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Post by propwash »

To answer your question steel_ram yes cold temps do effect shot placement. It has to do mostly with the humidity and density of the air

Also I'm not a pro but I shoot what my gun likes best year round and when I practice I record my settings along with the temp and humidity level and keep this info for future conditions. I shoot Wolf MT and it will go from a 75 degree 100M zero to shooting about 4 inches low at 35 degrees at 100M about an inch low or slightly more at 50M....I know this happens so I practice for it and record the data.
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Post by propwash »

Just wanted to add that some BR shooters keep ammo in a cooler with a hand warmer pack in cold temps and switch to a cold pack in hot weather.
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SK/Wolf

Post by dwl »

Just had a match at Kaysville, UT on Saturday. When shooting started at 0900 the temperature was 47F and my SK Standard Plus was shooting low and wide at 100 m. I was looking for it but the size of the groups was disheartening. I recorded my zeros as best I could.

The match started at 1000 which is exactly when the sun crested the ridge, shining right in our eyes. The light in my eyes must have illuminated my brain. I placed my loaded magazines in my pants pockets and placed the boxed ammo in the sun. That did warm things up but those chickens all go shot in the feet at 50m. I had to adjust the zeros up again.

Later in the match, the ammo, air and gun got warmer. We finished the match at 67F and I had to lower my earlier zeros back to normal levels.

While the need for a good cold weather ammo seems apparent, the really difficult task is to keep the head cool and shoot the best match you can when something isn't going well.

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Oops

Post by dwl »

Wow! I wrote the same thing the other day! Am I losing it?
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