In Houston, the stable ground temperature is around 70-72 deg, which is perfect -- simply pump water or antifreeze through it and then blow interior air over the coils.
If the Marlin bolt rifle malfunctioned when cold at a mere 20-30 deg F and functioed at a warmer day, say 60-70 deg F, then there is something wrong with the lubrication, cleanliness, and maintenance of the rifle, not the design and constuction. metal does not expand and contract significantly at those temperature ranges.
HAs been cold as well diger's A = = here and had the deepest snow in l4 yrs. (22 days temps never got above 30 deg) Still some o north banks.
Bake it for 15 mins in a preheated oven @ 190 deg celsius.
Tell Haim Saban/AIPAC that GW will turn up the thermostat in Tel Aviv to 120 deg Fahrenheit and watch what happens.