308 & a 72" Barrel Experiment

MDT Builds Longest Rifle Ever | Field & Stream (fieldandstream.com)

“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 …


Just goes to show how much energy is lost on a short barrel. I try to stay around 4” for EDC.

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Well the barrel on my M14 is 20" and it served fine out to a 1,000yds in Nam and th L10 I made from the ground up with a 80% lower also with a 20" barrel puts a round downrange same as the M14,and also made a AR15 with 89% lower and a 20" barrel and it is good for 500/600 Yards zeroed in with 62gr green tip

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