Discerning rifle builders frequently want to know what kind of barrel life they can expect when purchasing a new Criterion barrel. We try to provide them with a detailed answer so that they can make the most educated selection to serve their intended needs and requirements. When exploring barrel life, it is important to ask how the rifle builder plans on using their barrel. Asking for an exact round count on how long a barrel will last is like asking a vehicle manufacturer how many miles a car will travel before the engine gives out. Is the driver planning on taking the car down the block to the grocery store once a week, or competing in rally racing and demolition derbies?
Barrel life is dependent on a number of factors, and it is very difficult to place an exact number on what an individual shooter can expect. Factors like the rate and volume of fire, maintenance procedures, ammunition selection, propellants/primers/bullets used, chamber configuration, material and finish (i.e. stainless steel, chrome lined, salt bath nitrided) environmental factors/exposure (i.e. salt water, rain, desert, etc.), are just a few elements that effect what kind of life you can expect from your barrel.
When is a Barrel Considered “Shot Out”?
It’s important to determine what the individual shooter’s expectation is for accuracy. The “Mil-Spec” standard for accuracy is 4.5 MOA at 100 yards with an M16A4. This would not be acceptable by Criterion performance standards.
Some shooters believe a barrel is effectively shot out when it is no longer capable of producing sub-.25 MOA groups with custom handloads (benchrest competitors). 3-Gun competitors may require the barrel to generate consistent sub-MOA groups with factory match ammunition. Some casual shooters may even be happy simply ringing a large steel gong at 100 yards. Criterion AR-15 barrels routinely achieve sub-MOA groups with most types of match ammunition and are frequently capable of generating sub-.5 MOA groups with quality handloads or match ammunition preferred by the individual barrel. Our pre-fit barrels should have no problem consistently shooting well under .5 MOA with handloads tailored to the barrel.
Criterion has several competitive shooters and employees (the author included) that send thousands of rounds through their barrels each year. Many of us have exceeded 10,000 – 20,000 round counts through a number of our barrels while still retaining a great deal of accuracy and muzzle velocity.
How Do I Maximize Barrel Life?
Proper maintenance will play a significant role in increasing or decreasing a barrel’s service life. While poorly executed maintenance may result in premature wear to internal surfaces, a lack of cleaning may also lead to corrosion and unserviceability. The Criterion guide to recommended rifle barrel cleaning procedures should serve to help maximize barrel life while keeping unwanted corrosion to a minimum.
If a Criterion barrel is properly broken in and is well maintained (as recommended on our website), it should perform well for many thousands of rounds. Barrels are both disposable and replaceable commodities, but the rate of replacement will vary widely depending on the rifle platform and chamber configuration. A rifle that is continuously fired at a cyclic rate of fire with high pressure loads at extreme velocities will wear out significantly quicker than a rifle fired at a slow rate of fire with low pressure loads at a low velocity.
Barrel treatments or coatings such as salt bath nitriding (a process that changes the material properties of the steel itself) and chrome lining (where a harder corrosion resistant material is applied to the internal bore and chamber surface) will serve to greatly increase overall barrel life. While these processes have traditionally not been applied to high performance precision rifle barrels, Criterion has invested a great deal of time and effort into refining and improving upon each finishing process, allowing for barrel performance on par with the world’s finest “in the white” 416R or 410 stainless steel barrels. With either process it is not unreasonable to expect a service life double or even triple that of a normal untreated barrel.
The area most impacted by frequent barrel use is the throat (the portion of the barrel where the bullet is seated in the chamber). As barrel use continues, the high pressures and erosion from bullets, gasses, unburnt powder, primer material, and other high velocity projectiles gradually wear away at the throat, requiring the bullet to “jump” further to reach the rifling as the throat erodes. One way to increase barrel life involves “chasing the lands”, or increasing the overall length of the cartridge to maintain a consistent distance between the ogive of the bullet and the lands of the rifling.
Here Are the Numbers!
Although barrel life varies considerably from rifle to rifle, here are some typical barrel life numbers reported by Criterion shooters.
M1 Garand (chambered in .30-06 Springfield): A typical rule of thumb that floats around the forums with these rifles pertains to the throat erosion (TE) gauges that collectors use to determine the amount of wear to the throat of each chamber. While a larger TE number is indicative of greater wear to the barrel, it does not necessarily mean the barrel isn’t a shooter. On average throat erosion will gauge a digit higher after each 1,000 rounds of normal use. Most shooters will replace these barrels when they gauge a 5 or greater. This leads one to assume the average barrel life for an M1 Garand chambered in .30-06 is approximately 5,000-6,000 rounds. Chrome lined barrels will typically last much longer.
AR-15 (chambered in .223 Wylde): As was mentioned earlier in this article, these barrels often feature a fairly long service life. Our 3-Gun competitors typically swap out their barrels after 17,000-19,000 rounds of limited volume rapid fire stages (30-60 rounds per stage on average). These barrels are normally salt bath nitrided or chrome lined. Our 3-Gun shooters typically expect sub-MOA performance with match grade ammunition as their performance criteria. Occasionally shooters participating in disciplines requiring lower rates of fire with reduced pressure loads will experience a barrel life well in excess of 20,000 rounds.
On the opposite end of the spectrum, many high power or service rifle shooters will swap out barrels quite frequently. These shooters trend toward untreated 416R stainless steel barrels, replacing them after 3,000 – 6,000 rounds.
.308 AR (chambered in M118LR): Shooters using these rifles typically experience serviceable barrel lives in the neighborhood of 5,000 – 8,000 rounds with an untreated bore. Chrome lined or nitrided barrels will last considerably longer before requiring replacement.
Barrels chambered in 6.5 Creedmoor tend to require replacement a bit more frequently. It’s not unusual to see a 6.5 Creedmoor barrel replaced in the neighborhood of 2,000 – 3,000 rounds with an untreated barrel. As with the M118LR chambered .308 AR barrels, chrome lined or nitrided models will last considerably longer.
Barrel Burner Cartridges (like the 6.5×284 Norma or many popular 6mm cartridges): Some shooting disciplines may require shooters to utilize extremely high pressure and high velocity loads that feature extremely short barrel lives. Some of the 6.5×284 Norma F-Class rifle builds we have assembled have required a new barrel after 1,500 – 1,800 rounds. These barrels require an extreme level of accuracy, so any degradation in performance is much more noticeable when compared to some of the more flexible shooting disciplines.
What sort of barrel life have you experienced with your Criterion barrel? Feel free to comment below with the type of barrel used, accuracy criteria, load ingredients, and average rate of fire.