MAKING AND USING THE COOLING ROD
When the weather is hot and you are trying to keep your rifle barrel cool enough to maintain accuracy,one of the tools often overlooked----and seldom mentioned---- is the COOLING ROD. This is an extremely simple tool and materials are readily available to build it.
Go to your local hardware store and purchase a plain 1/2" aluminum rod, be sure it is free of anything that would cause damage the inside of your barrel, put a handle on it if you choose and you are pretty well set.
There are very few rules when using the rod,just slide it in the barrel between shots and it will "wick" away the heat from the inside. It is very important that the rod itself must be kept as cool as possible, use a fan, run cold water over it---never ever leave it IN THE SUN!!!!
This is by no means a "cure all". You still need to shoot early and late and keep your rifle as cool as possible, but it is "one more thing " you can do to help cool your rifle on those hot days. Best of luck in battling the heat.