Thanks in large part to movies and television, the misconception that firearm suppressors slow bullets down or hurt accuracy is extremely pervasive. In this “The Truth About…” episode, I dive into silencer ballistics.
Watch the video embedded above, or click HERE to view it on Rumble. Visit Silencer Shop for the best prices and the easiest, most streamlined suppressor buying process in the country.
By the way, we’ll be launching a “studio” video like this one every Monday afternoon and a range video (like last week’s shooting tips for optics-equipped pistols) every Thursday afternoon. Subscribe on Rumble to see ’em before their associated TTAG articles go live.
Although not the common effect of silencers, some can slow the bullet, such as the MP5SD. It has ports drilled in the barrel just after the chamber, which bleed off gas into the chambers of the integral suppressor. This slows many standard loads to subsonic speeds. Other integrally suppressed barrel designs, like the Ruger 10/22 ISB, are essentially a shorter barrel with a suppressor attached at the end, but those don’t really slow the bullet — you need to do an apple-to-apples comparison with a 10″ barrel instead of counting the full 16″ length as barrel.
In their defense 14.5 and 16 inch barrels are more common than integrally suppressed setups.
You’re right, but those examples aren’t the effect of the silencer. Rather, the bullet in those examples is slower because the gun has a ported barrel or a shorter barrel. I should have been more explicit in the video!, but the question I intended to answer was whether the addition of a silencer to an existing gun changes velocity or accuracy from that gun.
Honestly I don’t think it’s so much movies and TV, but either video games or more likely simple fudd lore. Think about it how often do you see suppressors affecting guns in movies and TV other then sound? I can’t think of a single one where a suppressed firearm was less accurate, and how would you even be able to tell if the projectile is slower since hell most of the time it’s instantaneous. Games on the other hand make tend the firearm weaker and less accurate (which I believe is suppose to simulate subsonic ammo and a point of impact shift though it’s such a cliché now half the time it’s probably just because that’s what’s expected). Fudd lore is most likely culprit though, with people not understanding subsonic ammo/point of impact shift
For me it was always detective or like CSI shows where they would perform ballistics testing from a murder victim and say something about the low penetration or the trajectory or whatever suggesting a slowed down bullet due to a silencer, so it must have been a professional assassin etc etc haha. Probably (if there even is a good explanation) the basis for this is the murderer using subsonic ammunition in a caliber that is typically supersonic, but for sure most viewers infer from these scenes that silencers slow down bullets and that’s at least some of where that myth comes from.
And for sure on video games! I know I played some back in the day where adding a silencer gave you the advantage of stealth but hurt your accuracy or lethality or whatever. Some of that is just video game laws (gotta be a trade-off for every equipment choice) but that one was pretty common and it helps create these sorts of widespread misconceptions.
“I dive into silencer ballistics”
More like sort of waded into the shallow end of the pool.
You left something out. The “silencer” (“suppressor” actually) you are talking about is the common type that attaches to the end of the barrel. The volume in these is too small to allow the hot gases to cool enough to affect pressure enough to significantly affect bullet velocity. Those generally do not affect the bullet speed significantly because the bullet leaves the suppressor very quickly (less suppressor to travel through, less time in the suppressor the more kinetic energy velocity is retained by the bullet) (even though the bullet velocity when the bullet leaves the suppressor will be a lesser value than the actual muzzle velocity).
By saying that suppressors do not affect bullet “speed” (velocity) you are implying that suppressors maintain the muzzle velocity.
All bullets begin to lose kinetic energy velocity the moment in time when they leave the muzzle end. The bullet leaves the barrel propelled by the pressure of the gases behind it, when that same pressure is no longer there after the bullet leaves the muzzle the bullet velocity begins to drop. This is why muzzle velocity is defined as basically “the velocity with which a bullet leaves the muzzle of a gun” and not after it leaves the muzzle of the gun. A bullet passes through an attached suppressor after it leaves the muzzle of the gun.
Yeah, someone is going to say “but but when I attach my suppressor to the end of the barrel it becomes an extension of the barrel.” No, just no no no … the suppressors you are talking about is not an extension OF the barrel, the suppressors you are talking about are an attachment ON the barrel.
Suppressors with more internal volume that allow the hot gases to start cooling sooner can slow the bullet significantly ’cause laws of physics dealing with hot gases. Generally the sooner the gases begin cooling and the larger the suppressor volume the more the bullet velocity is affected (because pressure drops as the gasses cool this is also how suppressors “suppress” sound because as the pressure drops the peaks of the impulse noise are attenuated). For example, the MP5SD integral suppressor has more volume and allows gas cooling sooner (by porting after the chamber) than the end-of-the-barrel attached suppressors you are talking about. The MP5SD integral suppressor can slow some supersonic rounds to subsonic speeds.
Suppressors still abide by the laws of physics. So its true the suppressors you are talking about do not significantly affect bullet velocity, but all suppressors do affect bullet velocity to some extent through, at the basics, the actions of the hot gases following the laws of physics and cooling as they are delayed. There is no such thing as a suppressor (not even my MP5SD example) that maintains bullet muzzle velocity like you seem to imply.
But, all this being said it was still a nice little video.
“volume” – in this context above means the amount of space that a substance or object or gas or liquid occupies. Like “the volume of that bucket is 1 gallon”
not volume as in sound level.
That’s simply not true. Measure the muzzle velocity with and without a suppressor attached and you’ll typically see a 1.5% to 3% increase in velocity with the can attached. The suppressor provides more time with gas pressure behind the bullet vs a bare muzzle and the velocity of the bullet continues to increase because of it. The mental gymnastics and guesswork on the physics of it isn’t necessary when this is such a simple thing to go and test. Just Google muzzle velocity suppressor and you’ll see tons of chronograph tests proving what I said in this video, both in articles and videos (including a YouTube video of mine where I tested this very thing in January of 2014 with a handful of different calibers and guns all showing consistent MV increases).
A ported barrel like the MP5SD is an entirely different beast from a bolt-on suppressor.
Unless you found a way to violate the laws of physics, what I posted is true.
You are not seeing “a 1.5% to 3% increase in velocity with the can attached”.
What you are seeing is the effect of the physics at play of sudden gas pressure release when the bullet clears the hole in the last baffle and the bullet is gaining energy into its full rotational spin speed at the beginning of its travel down range as it leaves the suppressor. What you are seeing is kinetic energy being realized that was still left over after the bullet was slowed in the suppressor, a certain amount of that converts into bullet rotational spin which in the conversion causes a temporary gain in velocity when the bullet leaves the suppressor. The physics laws of thermodynamics at play, energy cannot be created nor destroyed – the energy not imparted to the bullet spin has to go some place to be expended and its expended in imparting a temporary boost in velocity.
The bullet can’t achieve that energy conversion in the suppressor because pressure is dropping behind the bullet at each baffle/chamber which slows the bullet down, its robbing energy from the bullet. This is because pressure drops behind the bullet as it passes through the baffles and that pressure drop creates a pressure differential between what is in front of the bullet and behind it – in short the pressure drop behind the bullet drops and creates a low pressure vacuum condition that places drag on the bullet from behind.
Newton’s First Law of Motion states that an object in motion tends to stay in motion unless an external force acts upon it. The bullet remains in motion through the suppressor in terms of movement forward but velocity is also an element of that motion and the bullets velocity is retarded by the drag placed on it by the low pressure behind (the “external force”, meaning external to the bullet and that’s where the low pressure vacuum is behind the bullet) thus affecting the bullet motion by slowing it even though the forward momentum motion is continuing.
Its impossible for a suppressor to not slow a bullet. All suppressors will slow the bullet below muzzle velocity as it passes through the suppressor.
A ported barrel like the MP5SD IS NOT an entirely different beast from a bolt-on suppressor in this respect. The MP5SD just does it differently and more efficiently due to the ports for earlier gas porting and the greater volume.
“Newton’s First Law of Motion states that an object in motion tends to stay in motion unless an external force acts upon it. The bullet remains in motion through the suppressor in terms of movement forward but velocity is also an element of that motion and the bullets velocity is retarded by the drag placed on it by the low pressure behind (the “external force”, meaning external to the bullet and that’s where the low pressure vacuum is behind the bullet) thus affecting the bullet motion by slowing it even though the forward momentum motion is continuing.”
meaning, in the physical world; If anything at all touches that bullet as it passes through the suppressor, anything even pressure differentials or hot gases or gas eddy currents from gases circulating in the suppressor or even normal air circulating in the suppressor, the bullet will tend towards not remaining in motion which from the bullet perspective is what is happening. It has to slow down in the suppressor, it has no other choice.
Unless you are claiming you have found a way to overcome and negate and violate the laws of physics – the bullet does for a fact slow down in a suppressor and does not speed up like you say.
Google videos or not, it is impossible for a bullet to not slow down in a suppressor and it is impossible for a bullet to speed up in a suppressor.
The speed up part especially. You can not add kinetic energy to a bullet once its been fired. This should be obvious, but there is that myth complete with google videos. The moment that bullet leaves the muzzle it has all of the kinetic energy its going to have, all it will ever have and that’s it. I guess the video guys never thought about this and said “hey, wait a second. How did the bullet speed up in the suppressor beyond the maximum it will ever have at muzzle velocity?”. The answer, and only answer, is it has not sped up in the suppressor.
An increase of velocity of a bullet in the suppressor would mean the suppressor was adding kinetic energy to the bullet. Its impossible for a suppressor to add kinetic energy, there is no energy to impart to speed up the bullet, a suppressor is basically a negative loss system and it sucks up energy as a result of cooling gases and pressure drops which is why it can suppress sound.
It is a myth that a suppressor can increase bullet velocity, period.
What you are seeing is not an actual increase in bullet velocity above muzzle velocity. Basically, the short of what I said in my other post about what you were seeing is this – You are seeing the laws of physics at play in converting remaining energy in a surge after being free from the suppressor after passing through the suppressor. You are not seeing the velocity actually increase as a result of passing through the suppressor.
In addition to the rest of my replies to you, I still can not get over that anyone would try to justify that a bullet speeds up in a suppressor. Just common sense alone and understanding how a suppressor suppresses sound would give a clue if the right questions were asked.
But it being a violation of the laws of physics for a bullet to speed up in a suppressor and impossible for it to happen, that aside – the physical side of whats happening as a result of those laws of physics:
“Measure the muzzle velocity with and without a suppressor attached and you’ll typically see a 1.5% to 3% increase in velocity with the can attached. The suppressor provides more time with gas pressure behind the bullet vs a bare muzzle and the velocity of the bullet continues to increase because of it. ”
That is absolutely not true, in fact it is impossible.
In my other posts above in reply to you for this I stated
“The physics laws of thermodynamics at play, energy cannot be created nor destroyed”
It is true that gas pressure is behind the bullet through the suppressor. But that gas is being delayed by the baffles/chambers, that’s what they are suppose to do. As the gas is delayed it begins to cool, the cooler the gas the lower the pressure. If the gas did not cool and the pressure drop you would not have any sound suppression. That’s the physics behind why your suppressor works to suppress sound, the gases being cooled to reduce pressure which attenuates the impulse sound of the weapon firing. You can not create energy in a suppressor, you can only convert it to heat (eventually). All the energy a bullet has, the maximum it will ever have is that it has at muzzle velocity. The moment in time that bullet leaves the barrel it starts loosing velocity, it has to.
You can not add energy to a bullet in a negative loss system (which a suppressor basically is), especially one, in terms of suppressors, with decreasing pressure through the system. If you could do that, the worlds energy problems would have been solved about 100 years ago – and you can’t do it because it violates the laws of physics as energy can neither be created nor destroyed. It can be expended in such a system in the form of conversion to another type of energy such as, for example, heat but you can not create energy in a suppressor and that is what you are saying with this myth that energy in the form of more pressure to speed up the bullet is being created.
So it is true that gas pressure is behind the bullet through the suppressor, but that pressure is decreasing through each baffle/chamber and not increasing. To speed the bullet up would mean the pressure would need to increase and it can’t, its energy has already been expended in the form of heat by the gases cooling because they were delayed. When you delay the flow of a hot gas in any open system (the suppressor is a partially plugged open system, the bullet is the plug when it passes through the baffle hole) it cools, plain and simple, and when it cools its pressure drops.
In terms of a bullet speeding up in a suppressor:
“The suppressor provides more time with gas pressure behind the bullet vs a bare muzzle and the velocity of the bullet continues to increase because of it. ”
This is not true. It is impossible for it to be true.
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