On the other hand, remember the factory declared the life of these weapons to be 10,000 rounds. That's why they are cheap- when they are done you toss it.
I was taught that barrel life was around 10,000 rounds, that was for the C1A1 rifle, later the C7. Meaning that accuracy will decrease beyond a point that cannot be corrected by sights. 10,000 rounds is reasonable for a rapid fire rifle. I found this from Lija precision barrels, FAQ.
Pete
QUTOE:
Q. What barrel "Life" in number of rounds fired, can I expect from my new barrel?
A: That is a good question, asked often by our customers. But again there is not a simple answer. In my opinion there are two distinct types of barrel life. Accurate barrel life is probably the type most of us are referencing when we ask the question. But there is also absolute barrel life too. That is the point where a barrel will no longer stabilize a bullet and accuracy is wild. The benchrest shooter and to a lesser extent other target shooters are looking at accurate barrel life only when asking this question. To a benchrest shooter firing in matches where group size is the only measure of precision, accuracy is everything. But to a score shooter firing at a target, or bull, that is larger than the potential group size of the rifle, it is less important. And to the varmint hunter shooting prairie dog size animals, the difference between a .25MOA rifle or one that has dropped in accuracy to .5MOA may not be noticeable in the field.
The big enemy to barrel life is heat. A barrel looses most of its accuracy due to erosion of the throat area of the barrel. Although wear on the crown from cleaning can cause problems too. The throat erosion is accelerated by he at. Any fast varmint type cartridge can burn out a barrel in just a few hundred rounds if those rounds are shot one after another without letting the barrel cool between groups. A cartridge burning less powder will last longer or increasing the bore size for a given powder volume helps too. For example a .243 Winchester and a .308 Winchester both are based on the same case but the .308 will last longer because it has a larger bore.
And stainless steel barrels will last longer than chrome-moly barrels. This is due to the ability of stainless steel to resist heat erosion better than the chrome-moly steel.
The benefits of deep cryogenic processing of barrels and the use of moly coated bullets in prolonging barrel life are discussed in our answers in this section on those specific subjects.
I thought it might be interesting to point out a few exceptional aggregates that I've fired with 6PPC benchrest rifles with barrels that had a number of rounds through them. I know benchrest shooters that would never fire barrels with over 1500 shots fired in them in registered benchrest matches.
I fired my smallest 100 yard 5 shot aggregate ever in 1992 at a registered benchrest match in Lewiston, Idaho. It was a .1558" aggregate fired in the Heavy Varmint class. And that barrel had about 2100 rounds through it at the time. Another good aggregate was fired at the 1997 NBRSA Nationals in Phoenix, Arizona during the 200 yard Light Varmint event. I placed second at this yardage with a 6PPC barrel that had over 2700 rounds through it at the time. I retired this barrel after that match because it had started to copper foul quite a bit. But accuracy was still good.
Incidentally, neither of these barrels had been frozen or had any moly coated bullets fired through them.
As a very rough rule of thumb I would say that with cartridges of .222 Remington size you could expect an accurate barrel life of 3-4000 rounds. And varmint type accuracy should be quite a bit longer than this.
For medium size cartridges, such as the .308 Winchester, 7x57 and even the 25-06, 2-3000 rounds of accurate life is reasonable.
Hot .224 caliber type cartridges will not do as well and 1000-2500 rounds is to be expected.
Bigger magnum hunting type rounds will shoot from 1500-3000 accurate rounds. But the bigger 30-378 Weatherby types won't do as well, being closer to the 1500 round figure.
These numbers are based on the use of stainless steel barrels. For chrome-moly barrels I would reduce these by roughly 20%.
The .17 and .50 calibers are rules unto themselves and I'm pressed to predict a figure.
The best life can be expected from the 22 long rifle barrels with 5000-10,000 accurate rounds to be expected.
Remember that predicting barrel life is a complicated, highly variable subject. You are the best judge of this with your particular barrel. Signs of accurate barrel life on the wane are increased copper fouling, lengthened throat depth, and decreased accuracy.