How much cool down time?

[wonderman4]

I use a Fluke IR thermometer to monitor the barrel temps with my goal of not letting the barrel heat more than 10 deg F over ambient.

When burning 110 grains or 13 grains of powder, one would be surprised at how much heat can build during a shooting session.

 

[Harvey Durham]

I am working with a 264 win mag testing loads. I know that heat can erode the throat. On a say 70 degree day how much cool down time between shots? For best accuracy on a cold barrel wile hunting how long between shots wile testing a load? If it is 1/4 in with a warm barrel and hits the same spot with a cold barrel, are we good?

I never shoot one of my guns over 5 times without letting it cool down. It'll last ages if you'll do that.

 

[Good]

I used an inferred thermometer to monitor my barrel in the middle of summer once. In 90 degree weather, 4 minutes was time for a consistent barrel temp. Obviously not a cold bore test but consistent enough for load development. I tested with a quick 3 shot group and then shot a 3 shot group next to it with the cool down periods and they were the same within a margin of error. For 80 degs or less, I wait 3 min between shots to get the same barrel temps.
Right before the season opens, I collect some long range drop data and zeros using the fairly quick 3 shot group method.

That's great! During load development, I set a 4-minute timer between shots as that felt consistent.

I do a quick warmup with a couple foulers back to back, then start timing

 

[jrock]

I do a quick warmup with a couple foulers back to back, then start timing

Me too. I've also used some paper towel tubes to cover the barrel to keep the sun off. worked pretty well. I didn't leave it on while shooting because I'm paranoid about things touching the barrel but its light enough that it probably wouldn't effect POI. Who knows

 

[ntsqd]

One less variable in testing is a good thing.

 

[terry 338rum]

some time ago I asked the same question of a well known custom gun maker because I was doing a lot of waiting after every shot for the barrel to cool. he told me that if the heat affected a shot string to any great extend I needed a new barrel. in a hunting situation the first shot is the important shot not the third or the tenth.

 

[crkckr]

Clean-Cold bore shots should be tested in as close as you can get to your usual hunting environment. That first shot can be #1 of a bug hole or 2" out of the group, depending on phase of the moon & how you hold your tongue - which is why you need to know.

Shooting rounds thru an already hot barrel is the quickest way to ruin a good barrel, period. You can monitor your barrel temp with a $15 IR thermometer from Harbor Freight, just be sure to check in the same place each time. If you can fry eggs on the barrel (or not leave your hand on it), it's way too hot! I will shoot until the barrel is getting hot to the touch, then run a patch damp with Hoppes (or similar) then pull the bolt and let the rifle cool down, which is where the IR thermo comes in handy. I seldom shoot one rifle, I usually have 2 or 3 with me so I can rotate them. Either that or just go back in the house & have cool one (soda, of course) while waiting, & maybe catch a couple UTube vids. Works great unless I fall asleep in my easy chair! There are definite advantages to having your own range in your backyard!
Cheers,
crkckr

 

[guide4u]

Lots of good information, I have been ultra conservative on cool down. This will help speed up and get a more consistent temp. Thanks to all, back to work next week (guiding) so playing with loads will slow way down.

 

[memtb]

Prairie, I was also going to suggest an inferred temp gun.....they've a multitude of uses other than this. They are not expensive, a great thing to have! Not exactly firearms related, but, if you are doing a lot of trailer towing, almost an essential piece of equipment.....from tire and wheel bearing temps, to rear differential/transmission temps if towing heavy in steep mountainous terrain! memtb

 

[jrock]

And a good cat toy too

 

[Tex LR]

As others mentioned, lots of variables on "how long to let it cool down". With that said, the "BarrelCool" has been a great purchase for me. They work very well. I bought a couple and they second as a chamber flag. Link below.

http://barrelcool.com/product-category/barrelcool/

 

[JJMoody]

Any thoughts to add regarding felt or measured temps on a carbon wrapped barrel?

 

[Rich Coyle]

I am working with a 264 win mag testing loads. I know that heat can erode the throat. On a say 70 degree day how much cool down time between shots? For best accuracy on a cold barrel wile hunting how long between shots wile testing a load? If it is 1/4 in with a warm barrel and hits the same spot with a cold barrel, are we good?

I use a small infrared thermometer. It is about the size of a tube of lipstick. I check before I fire it by aiming the thermometer at the barrel right above the fore end with the rifle standing vertical with the bolt open. Then I don't fire it until it gets back to that temp. Warmer days takes longer. Sometimes much longer than cooler days.

 

[Hespco]

I have a Rem 700 264 mag I bought new in 1964. It has taken ton's of game & will still shoot an inch or better. I have NEVER EVER shot more than three shots with out a complete cool down. One of my cool down tricks is using 70 or 90% rubbing alcohol. Soak a rag or paper towel with alcohol. . Liberally wipe down the barrel repeatedly for 4 to 5 minutes. Maybe a couple more. You will notice considerable barrel cool down as the alcohol rapidly evaporates & carries heat away. Leaving the bolt open with the barrel pointed up or down creates a flue like draw of air thru the bore as you wipe down. If you have a carbon ( blued steel ) barrel be sure & wipe it down with some gun oil when finished as the alcohol removes oil.