Ballistics by the inch: a $15,000 ballistics experiment

Steve Johnson
by Steve Johnson

Ballistics by the inch is an exhaustive ballistics experiment done by Jim Kasper, Jim Downey and Steve Meyer.

We decided to test thirteen common pistol calibers, each over a range of barrel lengths from 18″ down to 2″, and each using a variety of ammunition (most of it “premium” ammo made for self-defense purposes). In each case we fired three rounds of a given ammo at a given barrel length, recording the velocity of the bullets at 15 feet with two commercial chronographs. If we did not get two reliable readings for each of three rounds, we repeated the process until we did. Altogether we fired over 6,000 rounds of ammunition.


Thousands of rounds waiting to be shot in the name of science.

They throughly documented the results which are available on the website online and as Excel and PDF documents.

Jim Downey told me the project cost in excess of $15000, not including the man hours put into it. I asked Jim if they were going to do the same for rimfire and centerfire rifle cartridges, his reply: “Heh – we’re all too exhausted by doing this one . . . but talk to me again in a couple of years. :)”.

These guys have created a great resource that will likely settle some bets, resolve some arguments and be referenced by gun blogs, magazines and books for many years, maybe even decades!

Steve Johnson
Steve Johnson

I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!

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  • K. D. K. D. on Nov 29, 2008

    There is nothing cooler than shooting rounds for an experiment. 6,000? You are my new hero.

  • Mikee Mikee on Dec 04, 2008

    I hope (before I go look) that they used multiple barrels of each length, and provided results based on exact bore size and land/groove dimensions.

    I think the cylinder gap on a revolver might vary enough from one gun to the next, or one cylinder to the next, that the repeatability of velocity could be affected.

    I also wonder if the lot to lot variation for ammunition can be a significant contributor to velocity differences....

    All in all, I look forward to reviewing the data

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