Some people are inappropriately hot. You don’t wear muscle shirts or strapless, no-back evening gowns to church. Some rifle barrels are inappropriately hot.
You can recognize these by the way they scatter bullets. Dress them properly and you can alleviate that problem. Hot barrels aren’t a concern for deer hunters. One and done. But they can be for varmint hunters and target shooters. When you’re running a 25-round long-range target course or picking off a hundred pasture rodents in an hour, you’re scorching your barrel. As it expands, accuracy suffers.
You can cool a barrel by waiting, but this can take 15 minutes, maybe 30 minutes on a hot day. You can cool it faster by running air through it. Some serious shooters carry a pressurized air tank to the field or range and blow air down their barrels.
Then there’s water. Yes, believe it or not, some serious volume shooters go through the trouble of rigging up pumps and hoses to flush water through hot barrels. Subsequent shooting heats the steel so quickly that rusting doesn’t seem to be an issue.
An easier water cooling system requires nothing more than a terry cloth towel and cool water. Wrap the towel around the hot barrel and soak it with water. In a minute or two, most barrels are cool and ready to shoot again. Using ice water kept in a cooler speeds things up a bit, but isn’t necessary. Evaporative cooling is pretty efficient.