I wrote a long-form article about an experiment that I conducted this summer to explore the question of whether or not recoil-management techniques have an effect on muzzle velocity. It involved a bit of data science (Python, pandas, plotly), some hardware (arduino, 3d printing), and math (LaTeX). I hope that this content is high quality enough to justify the time you spend reading it, and how much time it took me to create it!<p>I’d love to hear your feedback and answer any questions!
Wow, fascinating article. I'm a little surprised that the bullet has left the barrel before the rifle recoils, but I guess that makes sense with the differences in mass.<p>It really does mean that my poor accuracy with a large caliber handgun is from flinching. I sort of thought it was from being unable to control the recoil but it sounds like that has no bearing on where the bullet is heading, and so I guess I'm just flinching in anticipation.<p>Btw, where do you live that you have a 300yd range? I'm jealous. Here near Chicago (well, NW Indiana) I mostly make do with small indoor ranges and a .22 rifle which is typically allowed, but would love to get into shooting larger calibers longer distances.
> Does one directly affect the other?<p>Thought experiments:<p>1. Bazooka-like barrel open on both ends with identical bullets shooting out each end. I would say that each bullet got approximately half the energy.<p>2. Fixed barrel, hard mounted, no recoil movement. Bullet should get about double the energy of (1). If you imagine the expanding gas between the bullets of (1) but then change it to operate in half the volume (split down the middle), the pressure would be double but not quite since combustion rates may differ.<p>3. Barrel with very long throw, very low spring force. Bullet gets most of energy, peak recoil force is low.<p>But always true:<p><pre><code> - Newton's third law: For every action, there is an equal and opposite reaction.
- Conservation of momentum: p = m v
considering impulses: F t = m = p / v, p = F t / m</code></pre>
"<i>Regardless, these results strongly suggest that the bullet is long gone before the rifle moves under recoil. How long gone? In my case, the bullet was already 23 ft (7 m) down range. This makes sense because the rifle is nearly 900x heavier than the bullet, so it cannot accelerate as quickly.</i>"<p>I've heard that before, but this is the first time I've seen actual data. Nice work!
Great article, shared it with some friends who are geeks and shooters.<p>The presentation of the information was well done, I'd say.
It's very nearly a proper paper, if you ask me.<p>Thanks for sharing!<p>I especially enjoyed the pictures of the arduino and gear setup.
Very cool experiment and excellent writeup!<p>You can also do some meta-analysis with all of the high speed video on YouTube. Get something like Tracker[0] to watch the barrel displacement while the bullet is travelling down the barrel. This video from SmarterEveryDay [1] provides some good examples.<p>I've watched tons of these vids and my basic observation is that there is some motion while the bullet is in the barrel, but as soon as it leaves you basically are left with a rocket trying to launch into the shoulder of the shooter. Even at high frame rates there's a perceivable increase in rearward acceleration once the gases start escaping.<p>Looking forward to future articles! Particularly with the improved accelerometer, it feels like there's a story in the gaps. I'm sure you've got plenty of ideas when you start a blog with that name, but here are a few I've been mulling about while chasing a lawnmower around the yard (some of these may be tired stories for folks into match shooting).<p>- Benefit of powder sorting for uniform and/or even distribution of grain size/weight (maybe via sieve or some kind of scattering method?)<p>- Benefit of tip conditioning in terminal ballistics (e.g. precision shaping/polishing)<p>- Building a press + strain gauge to push bullets through barrel to characterize impact of variations in diameter/length on energy required to make the trip.<p>Last bit of spam from me. I did take a quick peek at the data. It looks like the area under curve measurement more closely correlates with velocity than peak pressure, but not by much. Not sure what the data column on the left represents in the PTC file.<p>[0] <a href="https://physlets.org/tracker/" rel="nofollow">https://physlets.org/tracker/</a><p>[1] <a href="https://www.youtube.com/watch?v=7pOXunRYJIw" rel="nofollow">https://www.youtube.com/watch?v=7pOXunRYJIw</a>
Is there any plausible physical model in which the difference in velocity of the bullet, on account of the recoil, could be greater than the change in velocity of the barrel over the time that the bullet is traveling in it? With the bullet taking 2ms to leave the barrel, and maximum recoil acceleration of 100 ft/sec/sec, that effect would seem to be at least two orders of magnitude smaller than the 20 ft/sec claimed in the article that prompted this project.<p>The one extra thing I can think of so far is that the recoil reduces the effective length of the barrel by the distance it has moved by the time the bullet exits the muzzle, but again that seems too small an effect (~0.2 millifeet, four orders of magnitude less than the barrel length?)
A long running argument: does leaving your silencer on cause a repeatable velocity delta?<p>I suppose I could just break out the screens and find out, but it's nice to argue over beers.