But with the increased popularity of the .223 Remington came factory loads with bullets weighing from 36 to 77 grains, and many shooters had no idea why their rifles shot so well with some loads and so poorly with others. Some figured it out pretty quickly. Eventually, faster twist rates like 1:9 became the norm for ARs, and even faster twist rates became more popular with shooters keen on shooting 75- to 77-grain projectiles from their .223s. Today, twist rate is a common topic of discussion at the shooting range. But twist rates played a major role in shaping the guns we shoot today long before they were a common topic of conversation. The 6mm Remington is one example that comes to mind.

Though the 6mm Remington's larger case capacity endeared it to handloaders, the .243 Winchester kicked its tail. The lackluster success of the 6mm Rem. can be directly attributed to its 1:12 twist rate that would not stabilize the 100-grain bullets deer hunters coveted. Heck, it didn't even do a good job of stabilizing Remington's 90-grain factory load.

Winchester's .243, however, had a 1:10 rate of twist, and it did a marvelous job of stabilizing 100-grain deer bullets as well as lighter varmint bullets. By the time Remington changed to a 1:9 twist rate, the damage was done. The .243 Win. dominated the 6mm market and still does to this day.

The .260 Remington is another victim of a bungled twist rate. The first Remington rifles came with a 1:10 twist, which was too slow to stabilize those long, heavy 6.5mm bullets. Remington switched to a 1:9 twist rate, but it was still too slow and provided iffy accuracy at best with 140-grain bullets. A 1:8 twist rate is a much better choice for the .260. Consequently, this phenomenal hunting and target round has languished in obscurity until recently because it was crippled from the start with the wrong twist rate.

So, you might ask, what does the barrel twist do and why is it so important?

The short answer is that barrel twist starts the bullet spinning at a given rate to stabilize the bullet. The rate must be constant for the utmost accuracy. An increasing twist rate will have little effect on accuracy except in the most extreme cases. However, a decreasing twist rate will almost certainly result in a dramatic decrease in accuracy.

The explanation for this is simple. According to barrel maker Dan Lilja, "If we look at a recovered bullet, we'll notice that the rifling cuts a partial helix in the bearing surface of the bullet for each land. The helix is on an angle matched by the twist in the barrel. If the twist rate decreased, the angle of this helix would decrease also and would effectively cut a wider groove into the bullet. This condition is undesirable because the bullet could then yaw while still inside the barrel. It would lack the full support of the barrel, especially on the driving side of the land. The yaw would be demonstrated by poor grouping on a target once it was released from the barrel.