The following post is offered for informational purposes ONLY!
ANY USE, MISUSE OR ABUSE OF THE FOLLOWING INFORMATION IS SOLELY AT THE DISCRETION AND AT THE RISK OF THE INDIVIDUAL CHOOSING TO PERFORM NON-STANDARDIZED PROCEDURES NOT ENDORSED BY THE MANUFACTURER OF YOUR FIREARM. PROCEED AT YOUR OWN RISK.
DO NOT, UNDER ANY CIRCUMSTANCES, USE ANY OF THE FOLLOWING PROCEDURES ON ANY SEMI AUTOMATIC, FULLY AUTOMATIC OR SELF LOADING FIREARM. DOING SO COULD PUT YOUR LIFE AND THE LIVES OF OTHERS AT SERIOUS RISK. IT COULD ALSO CAUSE PERMANENT AND IRREPARABLE DAMAGE TO YOUR FIREARM.
A Boresnake is one of the most useful tools you can have at the range on hot summer days here in Texas.
When your barrel gets really hot and the Sun is too strong to let it cool properly, dip the snake in ice water (try to keep the pull string dry) and pull it into the bore, inserting the string from the muzzle end and pulling toward the chamber.
Keep the muzzle pointed down once you get ahold of the brass weight at the action end. DO NOT pull it all the way through like the directions say, pull it until you see the "poofy", wet part of the snake get into the chamber, then stop.
Let it sit for a couple of minutes with the muzzle down, once your barrel is cool, reverse directions and pull the snake out of the muzzle.
Now run a dry snake through in the normal way a couple times and continue shooting.
For the cooling snake, I usually use one that's smaller than bore size since I'm not looking for any cleaning action from the brush portion. Even a .22 snake has enough body diameter to be snug in a 30 cal bore and it'll actually hold more water and cool better than one designed to fit the bore.
If you use this method, be careful so that you don't get any water in your action and MAKE SURE THE WEAPON, ESPECIALLY THE BORE, IS COMPLETELY DRY BEFORE SHOOTING!
I've never used this method on anything other than bolt actions and single shots. I STRONGLY CAUTION ANYONE ELSE FROM USING IT ON ANY FORM OF SELF LOADING ACTION!
Water, being an incompressible fluid, could do all kinds of things if it collected in a gas or recoil system.
None of those things would be good for you OR your rifle.