Basic Gun Silencer Physics

Basic* Gun Silencer Physics

Hi! If you have come here it is more than likely you are interested in this subject.

To that end I have a newish channel where I will try and focus upon the fact and not the BS about silencers and moderators for PCPs.

To help me do this  I will over the course of time present preliminary results from testing certain real gun silencers and discussing their physics compared to what might be happening within a PCP silencer/moderator. To make this easier for me, i will mostly just use the term silencer regardless of any gun definitions, true definitions of the word; because the term silencer is mostly interpreted with noise reduction when used in conjunction with firearms.

If you want to learn some basic stuff about gun silencers Vs PCP silencers then please visit here

As a scientist I have crazy curiosity about many things and one of those is trying to understand the dynamics within a silencer, especially a PCP silencer.

There are countless designs of PCP silencers, just like that for their firearms counterparts. Many manufacturers would have you believe isn their "witchcraft"  Vs their competitions.

The fact is, the ballistics of a PCP slug or pellet is entirely different to that of a deflagration event, ie put simply the rapid combustion of fuel within a gun cartridge. 

Thus PCP moderator/silencers do not have to confer to similar designs as those seen for effective (as apposed to BS)  firearm silencers. In fact too much "stuff' inside of a PCP silencer may impede the velocity of the slug significantly and just unnecessarily weight the barrel down. In many PCP's significant noise is generated from the hammer strike and this noise can only be attenuated by insulting the region of the weapon with some dense material, something which is more than likely not possible to do.

*BTW I say basic and it is very basic physics because the physics involved in high pressure air travelling at great velocity (even if it is sub sonic velocities) is difficult to model accurately and many flow rate characteristics change over 100m/s and we are certainly dealing with velocities far greater than 100m/s. However, when trying to design a proper silencer, engineers must take into account the specifics otherwise it is just "bucket chemistry" at the end of the day or "bucket mathematics", or however one wants to put it but certainly not real science.

For a real firearm, the projectile usually travels ahead of any expanding gases, as to the delay of exiting of the gases behind the projectile, and hence a delay and reduction in the sound pressure wave, proper internal design is NOT a fluke.