deviation in cold .....5 degrees

[Ruslow]

wondering if anyone has checked their fps in really cold conditions [5 degrees]. Just came back from range and the labradar showed 20fps deviation,but when in 50-70 degrees it is less than 10. Is this normal?thanks Stan

 

[J_D]

Yes. Shot a match at 19 degrees recently. Initial fps was 40 fps slower than average. I just kept adjusting it an about 5fps as it warmed up until it hit normal speeds.

R50 showed higher variation than

 

[Ruslow]

But what was your fps spread mine is 20+fps vs maybe 10fps in warmer temps.

 

[grauhanen]

But what was your fps spread mine is 20+fps vs maybe 10fps in warmer temps.

Comparing small sample sizes often gives unreliable data.

When it's colder, all rounds will be slower. When it's warmer all rounds will be faster. With large samples, the standard deviation and extreme spread should be similar in both.

 

[littlepod]

In the cold my SDs tend to be a little higher but not too crazy. Fps drops is about 1fps per 2 degrees.

 

[Buckhead]

It's normal for the SD to increase with colder temperatures. I have shot 22LR in temperatures down to -30 degrees Celsius. Some ammo is far more sensitive than others. SKLRM is one of the worst in cold temperatures. SD's could go to 30+ in colder temperatures.
You can mitigate this somewhat by using biathlon ammo like SK Biathlon or ELEY Match Biathlon, depending on the temperature.
Eley ammo seems far less temperature sensitive that some Lapua or SK products.

 

[Emerson0311]

wondering if anyone has checked their fps in really cold conditions [5 degrees]. Just came back from range and the labradar showed 20fps deviation,but when in 50-70 degrees it is less than 10. Is this normal?thanks Stan

Yes, my experience has been the same, aside from the first shot. I run my Garmin occasionally during the day as the temp rises and velocities increase.

 

[Emerson0311]

It's normal for the SD to increase with colder temperatures. I have shot 22LR in temperatures down to -30 degrees Celsius. Some ammo is far more sensitive than others. SKLRM is one of the worst in cold temperatures. SD's could go to 30+ in colder temperatures.
You can mitigate this somewhat by using biathlon ammo like SK Biathlon or ELEY Match Biathlon, depending on the temperature.
Eley ammo seems far less temperature sensitive that some Lapua or SK products.

I keep my boxes of ammo and loaded mags in inside pockets at those temps. It is unscientific, but the it helps.

 

[Buckhead]

I keep my boxes of ammo and loaded mags in inside pockets at those temps. It is unscientific, but the it helps.

I keep them in an inside pocket as well, much of the time with a hand warmer packet. Helps a bit, but once it's -20 all bets are off. I'm just a sucker for punishment I guess : )