Barrel Length vs. Velocity

By G&A Staff

“How much velocity do I lose if I shorten the barrel on my AR?”

The answer ranges from the precise, if wrong, “You lose 25/50/75 feet per second per inch” to the realistic “It depends on the caliber” to the resigned “I don’t have a clue,” which is at least an honest answer. To actually find out usually requires taking barrels of different lengths and testing them side-by-side. The problem is this: They are different barrels.

I built two identical.38 Super competition 1911s with barrels from the same production lot, both fitted by me. Everything was identical, not just similar. Yet one produced 100 fps more speed, with the same ammo than the other. Rifles are no different.

This test is different, a test of a barrel not just comparable, not just from the same company, but the same barrel. I’m destroying a perfectly good barrel in the name of science. And not just a perfectly good barrel — an expensive one.

The Barrel

The barrel is made by White Oak Armament (WOA), a well-respected barrel maker based in Carlock, Illinois. This 26-inch stainless match tube has a 1:8-inch twist and is notched on the lathe at 1-inch intervals to make it easier …Read the Rest

Source:: Guns and Ammo