does a silencer affect the bullet velocity?

The other night I watched the Sentinel. In it an Secret Service Agent gets shot and killed on his own front door step. When they were investigating the murder, another SS agent pulled the bullet out of the wooden door jamb and made a comment to a police officer/detective something to the effect that there must have been a silencer used. He said that the reason that he knew that was because if the gunman hadn't used a silencer the .45 bullet would have penetrated the door frame.
Is there any truth to that statement? Does it slow the speed of the bullet down when a silencer is used or is that just another hollywood attempt at sounding intelligent when they really don't have a clue.
I'd appreciate any thoughts, facts on that issue.
Thanks!

[Echo5Oscar]

In order for a firearm to be truly "silenced", you must use sub-sonic ammo. That is, ammo that doesn't "break the sound barrier". This ammo would definitely have less penetration.

That's my understanding of it. Correct me if I'm wrong, anybody.

[beardman2]

If memory serves "silancers" generally increase velocity. Not the other way around.

[amishclark]

i don't know what the sentinel is, but it is my understanding that a silencer only increases velocity and accuracy...longer barrel and all that...

[jdavionic]

I may be wrong but I believe that silencing a shot involves 2 things. First, you want to eliminate the noise associated with the pressure blast coming out of the end of the barrel. The silencer essentially is a baffle the bleeds it off more slowly than without one. The second item needed is to reduce the velocity of the bullet to subsonic, which the silencer on the end of the barrel does not do.

So to answer you specific question, I believe the silencer actually increases velocity since you are extending the length of the barrel & more gradually relieving the pressure behind the bullet. However, you need to reduce the velocity of the bullet itself in order to achieve a silenced shot.

Admittedly this info is off the top of my head. The more experienced folks may call BS on this input & I would take their word over mine, if based on more extensive knowledge of the subject with more experience.

[JD McDorce]

Originally Posted by jdavionic

First, you want to eliminate the noise associated with the pressure blast coming out of the end of the barrel. The silencer essentially is a baffle the bleeds it off more slowly than without one. The second item needed is to reduce the velocity of the bullet to subsonic, which the silencer on the end of the barrel does not do.

Relating it back to the original post, if it was a .45 bullet and we assume that it was a .45 Auto cartridge, it is a fairly good conclusion that the bullet was traveling at subsonic speeds to begin with (referring to the second item). The ultimate effect on velocity as a result of use of a silencer is a result on a couple of factors: longer barrel to accomodate the silencer plus the position of the first baffle could lead to higher velocity (largely dependent on powder burn rate), while contact between the bullet and the inside of the silencer after the first baffle could lead to reduced velocity due to drag. At the end of it all, I would expect a high quality silencer to have a negligible effect on velocity.

[einheit 13]

Silencers work with sub sonic ammo.....drastically reduces noise levels at the muzzle, its up to the ammo after that to be 'quiet' Silencers have very little to 0 effect on velocities, a silencer is nothing more than an expansion chamber for the exiting gasses, sometimes fiiled with water or a 'matting' to 'muffle' the sound and cancel the pressur waves associated with the muzzle blast. depending on the type of silecer they will force the gases back down the barrel, some types require heaveir recoil spring so the action will work like its supposed to.

Using a silencer on 'standard' ammo will slightly muffle its sound and will eliminate most of the muzzle flash. More like a dull thud than the typical crack, and make the pressure waves (sound) spread out faster so the sound won't travel as far since it will move more in a radial patter than in a conical pattern. You will hear more sound to the side of the weapon than in front or behind it.

[nightraider]

Originally Posted by einheit 13

Silencers have very little to 0 effect on velocities, a silencer is nothing more than an expansion chamber for the exiting gasses, sometimes fiiled with water or a 'matting' to 'muffle' the sound and cancel the pressur waves associated with the muzzle blast.

From everything I've read about suppressors, einheit13 is on the money. Suppressors generally have little effect on the bullets velocity. Typically the loudest thing on a gun when using a supressor with subsonic ammo is the sound of the action moving back and forth.

[Loves2Shoot]

ps. They don't make the barrel "longer" they leave the rifling as they enter the exapnsion chamber, thus leaving the barrel at that point. They make the gun longer, but it doesn't improve the accuracy or velocity that I've seen. .45 are a good suppressed round because they are heavy slow moving bullets and are easy to have some punch and still be subsonic.

[jdavionic]

Originally Posted by nightraider

From everything I've read about suppressors, einheit13 is on the money. Suppressors generally have little effect on the bullets velocity. Typically the loudest thing on a gun when using a supressor with subsonic ammo is the sound of the action moving back and forth.

One aside with respect to the above comment, I've used the CB Long (CCI subsonic 22LR) ammo in my 10/22 without a silencer. It's works quite well and there's not enough energy to move the bolt assembly back - hence no mechanical sound of another round being chambered.

To give you an idea of how quiet it was, we had a "pest" that would cause noise every morning. Despite many non-lethal attempts to convince it to leave, it just kept causing problems. While my wife & kids were sleeping in the early am hours, I shot it from our upstairs guest room window (which is where all the bedrooms are located). No one heard a thing, not even the pest