Difference in Velocity: 18 inch vs. 16 inch AR Barrel| Gun Talk

Published on May 17, 2018
Duration: 2:42

This guide details a test comparing the muzzle velocity of .308 Winchester rounds fired from 16-inch and 18-inch AR-style barrels. Expert analysis from Gun Talk Media highlights that a 2-inch barrel length difference yielded approximately 100 fps, a difference deemed negligible for most hunting scenarios but potentially relevant for extreme long-range applications.

Quick Summary

A 2-inch difference in barrel length on .308 AR-style rifles, comparing 16-inch to 18-inch, resulted in approximately a 100 fps increase in muzzle velocity. This difference is often negligible for hunting but can be a factor in extreme long-range shooting.

Chapters

  1. 00:00Introduction: Barrel Length Velocity Test
  2. 00:21Test Rifles and Ammunition
  3. 00:5616-inch Barrel Velocity Results
  4. 01:3518-inch Barrel Velocity Results
  5. 02:12Conclusion and Analysis

Frequently Asked Questions

What is the typical velocity difference between a 16-inch and an 18-inch .308 AR barrel?

Testing with 175-grain OTM ammunition showed that an 18-inch barrel achieved approximately 2530 fps, while a 16-inch barrel averaged 2423 fps. This results in a difference of about 100 fps, favoring the longer barrel.

Does barrel length significantly impact hunting performance for .308 AR rifles?

According to expert analysis, the approximately 100 fps velocity difference between 16-inch and 18-inch .308 AR barrels is generally considered negligible for most typical hunting scenarios and distances.

When might the velocity difference between 16" and 18" .308 barrels matter?

The velocity gain from an 18-inch barrel over a 16-inch barrel, while small, could become more relevant for extreme long-range shooting where every bit of energy and velocity retention is critical for accuracy and terminal ballistics.

What equipment was used to test barrel length velocity differences?

The test utilized an Oehler Model 35P Proof Chronograph to accurately measure bullet velocities. The rifles tested were a Stag 10 with an 18-inch barrel and a Stag 10S with a 16-inch barrel, both chambered in .308 Winchester.

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