there was another thread on that recently Dick.
 
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 My take on it is that unless you are shooting the special biathlon ammo your cold ammo will show some degree of loss of performance.  There just a lot of un-rectified variables.

There was some discussion as to exactly why.  Two general schools of thought,  one is that the propellant is less efficient when cold. The other that it is the cold lube that slows the bullet down. I think it might be either, or both, or something else entirely, but I suspect the lube is the main factor. The amount of chill might also make a difference; though I'd guess that chemical changes in the powder would occur at lower temps than lube stiffening.
   
My personal experience is that a cold barrel and cold 22 rf ammo shoots low (and frequently to the left) in any of 5 or 6 different 22s I have used off the bench.   the amount varies with ammo and also the size and weight of the barrel.  For me, as the barrel warms up the bullets move up and to the right back to the previous warmed-up-gun zero. 
 In really chilly weather   sub 40 mornings on the Etna Green range with my heavy barrel bench rifle or one of the heavy barrel schuetzens it can take a whole bunch of shots to get back on zero. enough of a cool off during relays can start the process all over

Keeping your ammo warm, in an inner pocket, under a coat might help some, if the barrel has warmed up and is holding temp. 
Taking a relatively warm rifle out of the clubhouse and feeding it warm ammo might make an improvement unless it was so cold that they begin to cool off faster than shooting will keep them warm.  I have usually left my shutting box on my covered bench overnight-----maybe bringing it inside might help

some day----some day---I'm going to find some of those stick on thermometers and try to get an idea on the actual barrel temps and how they change. This cold barrel/cold ammo thing with the 22s really intrigues me.  {I waste too much ammo trying to get my bench gun up to working temp at the Spring match----and the Fall one this year}