Barrel Cooler

I think it's an accepted idea that hot barrels and cast bullets aren't the perfect combination and in a recent discussion with Jeff Bowles he mentioned he ran a small fan on his barrel between relays to cool it down. It sounded like a pretty good idea to me and since the current cartridge/velocity combination I'm playing with (30x47-17 twist-170 gr LBT bullet-2575 fps)  heats the barrel up real fast it sounded like a good idea.

After wandering around Menards for a while I found an air mattress pump that Coleman sells that runs on 4 D batteries (called the 4D for some unknown reason) that puts out a heck of a lot of air. In the plastic hose aisle I found a piece of 3/4 OD -  5/8 ID rubber hose that's a perfect fit for both the pump outlet and the action. So far I've tried the fit it in both my Stolle and a 98 Mauser action and the hose is a good fit in both so assume it'll work in any center fire action.  

To test the thing out I picked up a barbecue thermometer with a 12 inch probe to insert in the barrel. I put O-rings on it because I didn't want to take any chances so the temp isn't actual barrel steel temp but air temp 12 inches in from the muzzle.  I wanted to somewhat approximate shooting in a match so to start I fired 5 warm up rounds and then four 5 shot groups 7 minutes apart.

After the warm up and first two 5 shot groups I inserted the thermometer after 5 minutes and took a reading after letting the thermometer sit in the barrel the final two minutes. Temp was 135 degrees. I then shot my final two groups, ran the blower down the barrel for 5 minutes, followed the same test procedure of 2 minutes with the thermometer and air temp. in the barrel was 100 degrees. It stands to reason that the barrel would have been much hotter after firing 10 more shots so in my opinion the cooler does a great job. Price at Menards was 9 bucks for the blower and 5 bucks for 10 feet of hose. I've run the thing for an hour and a half with the cheapest D batteries I could find and it still puts out enough air to cool a barrel so overall not a bad investment if barrel heat is a concern. I've included a couple of pictures if you're interested.

Accuracy wasn't part of the test and the 30x47 is still giving me fits but I've also included a photo of the test target. Lower left was the warm up, top two are the first and second group, and middle and lower right are the last two. The flyer thing is something I have some ideas about and hope to have solved next time out but as you can see cooling the barrel doesn't seem to hurt and from what I've seen so far really helps in my case.

What got me going down this path is that in the second match I shot this gun in my first 10 shot group at 100 yds was .725, the second was 1.100. After a lunch and an offhand match my first 200 yd 10 shot group was some where in the 2.2 range and my second was almost 3 inches. Conditions were pretty bad but maybe it had something to do with heat. Time, and a small investment, will tell.

I couldn't figure out how to attach 3 pictures so will place them in separate posts.

Pat