This thought-provoking piece is one of 15 most popular Daily Bulletin articles over the past 12 months. This story is republished today for readers that may have missed it. Here’s a little-known fact that will surprise even the most experienced gunsmiths. Your barrel wears out within seconds. The actual bullet in barrel time of a match barrel is only a few moments. You may ask, “How can that be?” You need to consider the actual time spent by bullets in the bore of the barrel during its useful life. (Hint: It’s not long). Bullet-Time-in-Barrel CalculationsIf a bullet is flying at 3000 fps it will pass through the barrel of a 24″ (two foot) gun in 1/1500th second. If you have 3000 rounds in your barrel, it would only take two seconds to operate the bullets. But it’s not as simple as that. The bullet’s average speed is not the same 3000 fps muzzle velocities because it starts at zero velocity, then accelerates through the bore. How long does it take a centerfire (with a 3000 fps muzzle velocity) to stay in the bore on average? The answer is.002 seconds. Varmint Al is a smart engineer who worked for the Lawrence Livermore Laboratory. This government think tank develops neutron weapons, fusion reactors, and other simple things. Varmint Al calculated that a bullet’s time in a barrel is less than.002 seconds on his Barrel Tuner webpage. Al writes: “The time it takes for a bullet with a muzzle velocity of 3300 fps to exit the barrel is 0.0011 secs, assuming constant acceleration.” The actual exit times will be longer because the bullet isn’t under constant acceleration. We will use.002 for our calculations, knowing that exact numbers depend on barrel length and muzzle speed. .002 is an average that, if anything errs on the side of a longer barrel operating life. If a bullet spends only.002 seconds inside the barrel for each shot and you have 3000 accurate barrel rounds, how long does the barrel last before it starts to lose accuracy? It’s a simple math problem: 3000 x 0.02 seconds = 6 secs. Gone in Six seconds. Want to cry now?
Six seconds. Six seconds is the time it takes for your barrel to “go south” (in terms bullet-in-barrel shooting time). We know that some barrels can last for more than 3000 rounds. On the other hand many.243 Win barrels and 6.5-284 barrels start to lose accuracy after 1500 rounds. If your barrel’s accuracy drops at 1500 rounds, it has only been working for three seconds. If you shoot a “long-lasting”.308 win that lasts 5000 rounds without losing accuracy, you get a whopping 10 seconds of barrel life. When you consider the actual firing time, a rifle’s barrel has a very short lifespan. Many people complain about the high cost to replace barrels. You can now complain louder about the short lifespan of barrels. Our analysis gives you a good reason to buy a new Bartlein or Shilen, for example. You can get a new barrel for your fine rifle.
