“Many also predicted that the long barrel would slow the round down because of friction. But out of the 6-foot-long barrel, the bullet traveled at 2785fps (185 fps faster than the estimated velocity on the box).”
"around the 42-inch mark, things started to drop off. After around 30 inches, every inch taken off of the barrel resulted in a loss of 15 fps, leaving the muzzle velocity at 2567fps at 19 inches. "
The title indicates they tested an 88" 308, which I initially confused for the length of the barrel, but it was a much “shorter” 72" barrel before they started cutting it off 1 inch at a time.
And for those that prefer the video version: Cutting The World’s Longest Rifle To Find The Perfect Barrel Length - YouTube
The video version is much better to me …