Sean Roach on December 18, 2020, 05:08:04 pm
I was just thinking about a popular meme, involving an astronaut with a Cuban flag, executing another astronaut while both are looking at the earth.

How would firearms function in space?
I'm not asking about the vacuum here, but rather the temperature.
In the shadow of the Earth, a metal handgun would, presumably, be pretty close to -100C, and in the sun, to 120C.
Now, I'm PRETTY sure that the autoignition temperature of smokeless powder, and our fulmination based primers, is well above the boiling point of water, and the gun SHOULD be able to take the not-all-that-hot temperature.

What about the cold?
Will the propellant ignite at -100C? Will the primer go off at that temperature?
Would the gun shatter?

Then there is thermal expansion to consider, and this applies to both the hot AND the cold.
According to one quickly googled website, (, steels appear to have a thermal coefficient of expansion of between 9.9 and 17.3, depending on alloy. Lead has a thermal coefficient of expansion of 26.5 to 29. I'm ignoring the copper because it's usually just a thin shell over the lead. At high temperature, after the gun has had a chance to equalize, would the gun jam when fired? At low temperature, would the gun lose accuracy as the bullet shrunk smaller than the barrel?