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Barrel Length and Velocity

Federal 223 Rem 5.56 55gr FMJI recently had an opportunity to fire the same 223 Remington ammo over a chronograph out of 3 very different barrel lengths, and recorded the muzzle velocity differences I observed.  The chronograph was an Oehler 35p, which is one of the most accurate in the industry.  The ammo fired was Federal’s 55gr FMJ ammo, and all of it was out of the same box. Here are my measured results:

Barrel Length (inches) Average Muzzle Velocity (fps)
20″ 3019 fps
16″ 2837 fps
7.5″ 2135 fps

Here is an inferred trendline based on the measured velocities for other 223 Remington barrel lengths.  5.56 barrels would likely be very similar.  The blue bars indicate actual measured velocities, and the gray bars indicate an inferred muzzle velocity.

Average Muzzle Velocity Loss By Barrel Length for 223 Remington

There is much debate on how much velocity is lost when you start chopping down the barrel, and there are even a few people that think velocity loss is a myth.  That is ridiculous.  Although the amount of loss for a particular cartridge and barrel length is still up for debate (and is debated fiercly on many forums) … the fact is that there is virtually always some velocity loss when you reduce the barrel length.  Now how significant that is, and whether it is worth it for your application is up to you.

About Cal

Cal Zant is the shooter/author behind PrecisionRifleBlog.com. Cal is a life-long learner, and loves to help others get into this sport he's so passionate about. His engineering background, unique data-driven approach, and ability to present technical and complex information in a unbiased and straight-forward fashion has quickly caught the attention of the industry. For more info on Cal, check out PrecisionRifleBlog.com/About.

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  1. Would have liked to see barrel lengths > 20″. I have three Rem 7 with 28″ barrels.
    Different chamber dimensions gave you different pressures from the same load but close enough.
    Ross Seyfried wrote a very good article as he progressively shortened a barrel in 1″ increments.
    I can not find it online to ref. but could scan and email if you desire.

    • I hear you, but that is all I had with me that day at the range. I actually don’t own any 223’s with barrels longer than 20″. I sent you an email though, and would love to see the data from the experiment Ross Seyfried did.

      Thanks for the comments!