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TheOldPro

Letting rifle barrel "cool off"...

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I've wondered about the standard on this for a while: when testing new loads, or simply sighting in your rifle or scope, how long is about right to let the barrel "cool off" between 3-shot groups? I know that "cool to the touch" is sort of the rule of thumb, but this will vary with those who do the touching. So does anyone have a sort of set ritual when it comes to this that has worked for them over the years?

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OldPro,

 

You'll probably get as many opinions on this subject as there are Forum members! There are several variables, and here in Texas, the ambient temperature is one of the most important. Today, a barrel will cool off rapidly. At the range in August, it may never cool off to comfortable touch. Each barrel and each firearm is different. Heavy barrels take a bit longer to heat up, but also take longer to cool down. How the barrel fits into the stock is important. If it touchs the stock, the change in temperature of the barrel can have a profound change in accuracy as it heats up and creates pressure points. Different calibers cool off more rapidly than others, because they burn different amounts of powder and create different pressures.

 

If you're testing a new load for some serious varmint or big game hunting, the "first shot out of a cold barrel" is the most important one, so you should let the barrel cool off, depending upon the weather, of course, for at least 3 minutes. See where subsequent shots impact the target while keeping the same aiming point. If you note a significant difference in point of impact, you may wish to extend the time between shots. As mentioned, this may be different for each firearm; your .243 may cool off rapidly; your 30-06 may take a bit longer.

 

If you're preparing to go on a prairie dog or ground squirrel hunt, where you may have the opportunity to shoot 2-300 shots a day, you should test the load, rifle and scope accuracy with a more steady stream of shots, waiting no more than 30 seconds or so, and, once again, see how the rig performs. Many p'dog shooters will take at least 2 or 3 rifles with them, and shoot one for 30 minutes or so, set it aside, and take another one for 30 minutes, just to spread the heat around.

 

There are no hard and fast rules for this timing issue, but there is general agreement that exposure to heat and pressure is what makes a barrel become "shot out." The casual shooter will rarely have the opportunity to shoot out a barrel. If he experiences loss of accuracy, it's most likely because the weapon needs a thorough cleaning.

 

Hope this helps.

 

Mike

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If I am working on a new load here is my ritual. I will shoot one shot, pull the case out, measure it with the mic., check the target through the spotting scope, look at the chrony reading, scratch a couple of notes, and repeat for a total of five shots. After the last shot I will make my make my final notes on my loading log, and clean the the barrel and start all over again. Does that give the barrel enough time to cool???who knows, but maybe that's why they call me crazy :wacko:

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At least one minute, sometimes more depending on the weather or sunlight. At my age, waiting also helps on the eyestrain.

 

jim

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Dear Crazy

 

Sounds reasonable to me............then again I would most likely be scratching something besides notes. :biggrin:

 

I do my testing a bit differently but not much. If I am shooting small calibers e.g. 6mm and under I typically shoot 4 or 5 shot groups. I don't wait much between shots. A bit of time lapses to take a peek through the spotting scope etc. But then I eject the case, load another one and settle in for the shot. When all is "right" I pull the trigger. It might be 10 seconds or 2 minutes between shots. Once I have shot the group I let the gun cool down by standing it vertically and generally removing the bolt to allow for the greatest air movement through the gun.

 

I don't typically clean the gun unless I am changing from one bullet or powder to another. If I am trying different weights of the same powder I just go ahead with the next group when the gun is cool or cooler. \

 

Not perfect but it is my methodology.

 

Rick

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