Without the barrel, all the other parts of a rifle are useless. In addition to allowing the propellant inside a cartridge to transfer its energy to the bullet, the barrel also is responsible for sending it on an accurate path and in the desired direction.

Most centerfire barrels made today are either type 416 stainless steel or type 4140 chrome-moly steel. All else being equal, the accuracy potential of the two types of barrels is the same. Both do, however, have their advantages and disadvantages.

Chrome-moly is a bit easier to machine because it is less susceptible to galling, but this presents no problem with stainless steel as long as it is properly lubricated during the machining process.

Stainless steel is better at resisting oxidation, but since it does contain a bit of carbon it will rust under severe conditions. Stainless is also a bit more resistant to bore erosion, so accuracy life can be a bit longer--how much longer depends on several factors.

Most barrel makers will tell you that when both types of barrels are properly maintained, the stainless barrel will withstand the firing of 5 to 10 percent more rounds before losing its accuracy. This is more important in a varmint rifle because it usually is fired much more than a rifle used for hunting big game. The bigger the cartridge for a particular bore size, the shorter the accuracy life of a barrel.

Given proper care, a good barrel will last longer than some shooters believe. Based on my experience, I'd say a top-quality stainless barrel in .233 Remington should digest upwards of 6,000 rounds before losing its prairie shooting accuracy, and I've known a few that lasted longer than that. A good barrel chambered for hotter cartridges such as the .22-250 and .220 Swift should deliver long-range accuracy to at least the 4,000-round mark, while a barrel in .257 Weatherby Magnum, 7mm STW or .300 Weatherby Magnum should still be delivering minute-of-whitetail accuracy at 2,500 rounds.

Several years ago I discussed barrel life with Earl Chronister who for several years held the world's record for the smallest 10-shot group of 4.375 inches fired from benchrest at 1,000 yards. A member of the Original Pennsylvania 1000 Yard Benchrest Club, Earl shot a rifle in .30-378 Weatherby Magnum and usually switched barrels every ,2000 rounds.

All you have just read on barrel life assumes three things: the barrel is not heated up excessively by a lot of rapid-fire shooting, its bore is properly maintained, and the barrel is a good one to begin with.

When it comes to determining accuracy potential, a close match between bore and bullet diameter along with end-to-end bore and groove dimensional uniformity are by far the most important. The surface quality of the bore is also important because bullet jacket fouling, which will eventually spoil accuracy, accumulates more slowly in a smooth barrel than in a rough barrel. But regardless of how smooth its bore surface is, a barrel will not deliver top-level accuracy if bore and/or groove diameter varies a great deal from chamber to muzzle.

By the same token, a barrel is not likely to be accurate if its bore diameter does not closely match that of the diameter of the bullet being fired. This is important with any type of bullet but more so with those of monolithic design such as the X-Bullet from Barnes simply because it does not obturate as freely to fill an oversized bore as a conventional lead core/jacketed bullet is prone to do.