Can sustained rapid-fire shooting with no cool-down period wear out a quality barrel more quickly? The answer is “Yes” according to Forum member LCazador, who did an interesting comparison test with two .243 Winchester barrels. He started off with two, identical, match-grade HV taper stainless barrels. Both were NEW at the start of testing, and LCazador shot the same load through each: 95gr match bullets with 38 grains of Hodgdon Varget. After giving both barrels the same, gentle 20-round break-in, 300 rounds were then fired through each barrel — in very different ways. Barrel condition and wear were monitored with a borescope.

Barrel One — Slow Fire, Cool Down Periods, Cleaning Every 50 Rounds
At the end of the 300-round test, Barrel One looked brand new. There was none of the severe fire cracking found in Barrel Two. This barrel was shot no more than 10 times without a cool down and firing was done at a much slower pace. Cleaning for this barrel was done every 50 shots.

Barrel Two — Fast Firing, No Waiting, Cleaning Every 100 Rounds
The second barrel, which received hard use and minimal cleaning, was severely damaged with severe fire cracking at the leade and throat. As a result, the barrel had to be re-chambered. This barrel was shot 100 rounds at time without cleaning and was shot up to 20 times in succession without a cool down.

LESSON LEARNED — Heat Kills Barrel Life
Don’t let your barrel get too hot, and keep it clean. One afternoon can ruin a barrel!

Monitoring Barrel Wear with Borescope
Some folks worry too much about what their borescopes reveal — many barrels do not have to be “squeaky clean” to perform well. In fact some barrels run better after ten or more fouling shots. However, a borescope can be very helpful when your barrel starts losing accuracy for no apparent reason. Forum member FdShuster writes:

“A borescope is a positive way of backing up your suspicions when the rifle starts to throw an occasional (soon followed by more frequent) wild shot. Using the scope is also an excellent way to determine that the cause is barrel wear and not simply a need for a concentrated cleaning session to remove built up copper and more importantly, carbon fouling.

I’ve had a few barrels that gave every indication of being shot out. But I ‘scoped them out and found the cause to be nothing more than requiring a good cleaning. They then returned to their usual performance. There’s no guessing involved when you are able to get ‘up close and personal’ using the scope. The borescope also provides an excellent view of the all-important condition of the crown. My borescope is one of the most valuable investments I’ve ever made.”

Can sustained rapid-fire shooting with no cool-down period wear out a quality barrel more quickly? The answer is “Yes” according to Forum member LCazador, who did an interesting comparison test with two .243 Winchester barrels. He started off with two, identical, match-grade HV taper stainless barrels. Both were NEW at the start of testing, and LCazador shot the same load through each: 95gr match bullets with 38 grains of Hodgdon Varget. After giving both barrels the same, gentle 20-round break-in, 300 rounds were then fired through each barrel — in very different ways. Barrel condition and wear were monitored with a borescope.

Barrel One — Slow Fire, Cool Down Periods, Cleaning Every 50 Rounds
At the end of the 300-round test, Barrel One looked brand new. There was none of the severe fire cracking found in Barrel Two. This barrel was shot no more than 10 times without a cool down and firing was done at a much slower pace. Cleaning for this barrel was done every 50 shots.

Barrel Two — Fast Firing, No Waiting, Cleaning Every 100 Rounds
The second barrel, which received hard use and minimal cleaning, was severely damaged with severe fire cracking at the leade and throat. As a result, the barrel had to be re-chambered. This barrel was shot 100 rounds at time without cleaning and was shot up to 20 times in succession without a cool down.

LESSON LEARNED — Heat Kills Barrel Life
Don’t let your barrel get too hot, and keep it clean. One afternoon can ruin a barrel!

Monitoring Barrel Wear with Borescope
Some folks worry too much about what their borescopes reveal — many barrels do not have to be “squeaky clean” to perform well. In fact some barrels run better after ten or more fouling shots. However, a borescope can be very helpful when your barrel starts losing accuracy for no apparent reason. Forum member FdShuster writes:

“A borescope is a positive way of backing up your suspicions when the rifle starts to throw an occasional (soon followed by more frequent) wild shot. Using the scope is also an excellent way to determine that the cause is barrel wear and not simply a need for a concentrated cleaning session to remove built up copper and more importantly, carbon fouling.

I’ve had a few barrels that gave every indication of being shot out. But I ‘scoped them out and found the cause to be nothing more than requiring a good cleaning. They then returned to their usual performance. There’s no guessing involved when you are able to get ‘up close and personal’ using the scope. The borescope also provides an excellent view of the all-important condition of the crown. My borescope is one of the most valuable investments I’ve ever made.”

Monitor Barrel Heat with Pocket Infrared Gauges
It’s the middle of summer, and temperatures are HOT around the country. That makes it more important than ever to monitor your barrel temp when at the range. 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.

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.”

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.

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.”

by Tommy Todd, Sierra Bullets Chief Ballistician for Sierra Bullets Blog
I have shot several disciplines of shooting competitions over the years and have learned a few things regarding ammunition and bullet function during this time. Frequently the matches I shoot require 40 to 100 shots before a person gets a chance to clean his rifle. Just as frequently, a good shooting match rifle will still shoot very good scores and groups with that many rounds fired through them. However, those guns do not deliver the same accuracy as when they were clean, but the drop-off in accuracy is not a huge change unless a set of accumulative issues arise.

In one situation, very dirty powder created more serious problems…

Pressure Issues — Extraction Problems Caused by Bad Fouling

Problem: Pressures Increased as Powder Fouled Barrel and Carbon Ring Formed
Solution: Clean Barrel Every Ten Rounds.

I witnessed a set of problems that occurred with a fellow competitor’s rifle at a recent F-Class match. He was using a large case capacity cartridge for the bore diameter and he was shooting a powder that was burning extremely dirty. As the match progressed, the carbon buildup caused most likely a carbon ring in the throat of the rifle and pressures kept increasing to the point that the cases were hard to extract, bolt lift was excessive, and eventually he quit shooting the rifle due to these issues. Accuracy also suffered as could be evidenced by the gun’s performance on target. This load looked fine when he was developing it, none of the excessive pressure signs appeared when he worked the load up, but he was cleaning the gun every ten shots.

When he was shooting multiple, 20-shot strings during the match is when the issues appeared. He was able to give the gun a thorough cleaning and the issues went away, for several rounds and then the pressures started appearing again. These pressure signs were not due to ambient temperatures as it was a cool spring morning and the temperature was in the low 40° range.

Accuracy Issues — Tune Lost with Higher Ambient Temps

Problem: Accuracy Lost When Outside Temp Much Hotter than When Load Developed
Solution: Pull Bullets, Reload Ammo with Lighter Charge

A couple of years ago, I attended a match early in the shooting season and it was unusually hot for that time period. I heard a competitor worrying before the match about his gun “blowing up”. At first I was concerned, but after thinking about what he had said I realized that he meant his “accuracy” blowing up, meaning he knowingly had loaded his ammunition at the top end of an accuracy tune that he established via a ladder test. The next day I asked him how his scores were and he said the gun was not shooting very well initially, but he had found enough equipment from friends that were at the match and had pulled the bullets, reduced the powder charge by a few tenths of a grain and re-seated the bullets and his gun was now shooting normally. The temperature difference between his home range the weekend before when he established his load and the match conditions was about 30 degrees and that was enough to cause an accuracy change at 1000 yards.

To 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.”