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June 15th, 2021

Don’t Roast Barrels! Monitor Barrel Temp with IR Thermometers

infrared pocket pen battery thermometer

Monitor Barrel Heat with Pocket Infrared Gauges
You never want to run the barrel of a precision rifle too hot. Excessive barrel heat kills accuracy, increases copper fouling, and can cause rapid barrel throat wear. Over the years people have devised various means to cool their barrels — from electric fans to dunking in tubs of ice water.

But how do you know if your barrel is too hot? Consider a “non-contact” thermometer that reads your barrel’s “infrared signature”. The small pocket-sized, non-contact Infrared (IR) thermometers are ideal for shooters at the range or in the prairie dog fields. Such thermometers are handy and inexpensive. You can buy these mini IR pen thermometers for under $15.00 from Amazon, Walmart, and other vendors.

infrared pocket pen battery thermometer

Pen-Sized Thermometers
Just 3.2″ long, and weighing an ounce, these handy IR pen thermometers are small enough to carry in your pocket, and will easily stow in any range bag/box. The Yidexin unit, sold by both Amazon and Walmart, can measure from -58 to 428 °F (-50 to 220 °C). You can also find considerably larger hand-held IR thermometers for industrial applications. These can measure up to 716 °F. But for quick measurement of barrel temps, we prefer the small pen IR thermometers that fit in a pocket. A little IR thermometer like this is a gadget that every serious shooter should have. Given the cost of replacing barrels these days (up to $700 for barrel, chambering and fitting), can you afford NOT to have a temp gauge for your match or varmint barrel?

TECH TIP — How to Get More Consistent Readings
When using IR Thermometers on shiny steel barrels, sometimes the polished surface throws off the beam, causing inconsistent readings. You can solve this problem by simply putting a piece of masking tape on the area where you take your reading. Some other folks use a grease pencil to create a non-reflective spot to read. Forum Member Jon B. says: “I used an Exergen infrared in the HVAC industry. Without the grease crayon they sold, you couldn’t get an accurate reading with shiny metals.”

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July 6th, 2019

Don’t Roast Your Ammo — Watch Temps in Hot Summer Months

Heat Map USA color chart

Well folks, it’s July 6th already — the means we’re moving into “peak heat” summer conditions. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.

Ammo cool storage

Bosch Insulated tool caseTo learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.

For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”

Powder Heat Sensitivity Comparison Test

Our friend Cal Zant of the Precision Rifle Blog recently published a fascinating comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s Enduron line of propellants.

CLICK HERE to VIEW FULL TEST RESULTS

The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested.

Precision Rifle Blog Temperature Stability test hodgdon varget H4350 Enduron IMR 4451

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