Do rifle barrel coolers work?

If you shoot a lot of rifles you’ve undoubtedly run into the problems associated with hot barrels; increased fouling, shots ‘walking’ and increased mirage. Whether or not thin barrel actually bend and change how well the gun shooting is subject to some debate (some barrel makers think it is the mirage moving the target around), but mirage is a very real problem, especially for shooters using optics.

The mirage problem is one I’ve dealt with a couple times a week for years. I shoot a lot and run my guns hot. Once a heavy barrel heats up, it takes a while for it to cool, so I’ve tried everything from spray cold water to packing the barrel with snow in cold weather. All of this has mixed success and seemed better as an idea than in practice.

I’ve noticed a couple of different battery powdered rifle barrel coolers on the market lately. These are very similar in design in that they use a small fan to force air down the barrel of your rifle after your fire it to help speed the cooling process. I decided to give one a try.

The coolers on the market come in different styles and shapes. Some have a power unit with a tube attached, others look like a large ECI (empty chamber indicator), but they all operate in the same basic way. When you are done firing, insert the cooler into the rifle and run it to cool it down.

The science behind the cooler seems to make sense, increased airflow over surfaces should accelerate cooling, but I wanted to see for myself. So I headed to the range with a cooler, rifle, a pile of ammunition and a Fluke IR thermometer.

My test rifle is a custom Remington 700 chambered in 6.5 Creedmoor I built myself.

The parts are as follows:

Since I mostly deal with barrel mirage issues in my shooting, I wanted to track how fast the barrel cooled down after each string of fire. I developed a quick test to see compare how fast the barrel cooled with the barrel cooler to without. I fired 10 shots, took the temperature of the barrel on where it met the front edge of the hand guard, set a timer for 3 minutes and took a final temperature when the timer rang. I’d conduct this same test 3 times for the barrel with the cooler, and three times for the barrel without the cooler. I alternated cooling sessions using the cooler and not using the cooler.

The IR thermometer I used is accurate to within +/- 2F. Ambient temperature was 80F.

These are my results.

If you take a look at the average rate of change for the barrel with the cooler versus without, there seems to be a slight benefit (-.2 degrees F/minute) to using one. I was hoping for more. To answer my opening question, yes, they appear to work a little.

When you start to look at the relative surfaces area of the inside of the barrel, versus the outside, you start to see the problem. To keep the math easy, let’s pretend we have a straight, unrifled barrel 26″ long (this keeps the math WAYYYYYY easier). It has an unrifled bore of .264″ and an outside diameter of 1.200″. The inside of our imaginary barrel has a surface area of 21.67 sq inches and the outside has a surface area of 100.28 sq inches. For a tapered barrel this ratio would decrease. That is nearly 5x the area available for cooling. I’m thinking perhaps some companies need to look at cooling the outside instead of the inside.

At any rate, the cooler I was using was well made and had a filter to prevent foreign debris from being blown into the rifle’s bore. At the end of the power unit is a hose that attaches to a modified cartridge case that is inserted into the bore. In my limited testing it seemed to work slightly better than leaving the rifle alone in a heavy barrel. I think it would probably work a little better in a barrel chambered for a larger bullet diameter and a thinner hunting type barrel.

If you’ve had better success from a barrel cooler, please, let me know. I’m interested.