When I first came to Africa, a lot of poachers were still using the old muzzle loading trade rifles like the Enfield Tower Musket in .577. These old guns had often been highly decorated with brass tacks, wire and beads--but more, I suspect, to hold them together than anything else. I had the opportunity to see a number of them examined in the police ballistics laboratory over the years, and when the bores were checked out with an endoscope the faint vestiges of rudimentary rifling could be seen. Here and there. And of course, while black powder was cheap and easily available, it was also extremely hygroscopic, resulting in a lot of very serious rust that wasn't apparent from the outside.
At one time, I even acquired one of the better examples and brought in bullet moulds and various accessories and shot it happily on the range for some years. It bore no serial number, but the number "17/99" was crudely stamped into the brass butt-plate. I was able to establish that this meant that it was the seventeenth Tower musket issued to the 99th Lanarkshire Regiment of Foot when they served in South Africa; when they left in the mid 1860s they upgraded to the breech-loading Sniders which was one of many reasons why these old Tower workhorses were so common in southern Africa.
And, of course, gradually the ubiquitous military rifles superceded the old muskets as rifles of choice for the poaching fraternity. The AK-47 is perhaps the most conspicuous. But in recent times, a number of heavy rifles have been recovered from gangs of poachers, and the most popular is the .375 H&H Magnum, which no doubt reflects the conventional wisdom that the .375 is the minimum acceptable calibre for use on dangerous game. Or maybe because they are less expensive--who knows or cares? And, these rifles are very often fitted with silencers, suppressors or sound moderators--call them what you will depending on the legalities of wherever you are.
Now, a silencer is a tool. It has a particular application, and whether this is truly understood by the poachers is another matter. A number of Zimbabwean private security companies issue their armed couriers with body armour. The fact that there may be no ballistic plates in the armour is seemingly less important than what their application is. They look cool, may be deterrents, and that's about it.
A lot of what many folks know about firearms--and this is very scary--they learned from Hollywood. Silencers are probably just about at the top of the list.
The noise of a gunshot is variable--from around 140 decibels for a .22 to around 175 or higher for some of the more powerful calibres. (If you are repeatedly exposed to firearm discharges and do not wear hearing protection, you will in time develop what is known as noise-induced hearing loss, and have trouble hearing speech sounds like "s," "th," or "v" and other high-pitched sounds. Your ability to perceive what you're hearing will be diminished.) The main reason to silence a firearm is not to protect the shooter but to keep others from hearing the shot. In reality, most silencers won't reduce the noise of a firearm's discharge to that barely audible "fttt" associated with James Bond--they normally take it down to around 120-130 decibels.
While a silencer may mask the sound of a gunshot --in other words in an outdoor environment it makes it very difficult to tell where the shot is coming from, and how far away it is, and at night it will also go a long way toward concealing the muzzle flash signature, it won't eliminate the noise of the shot unless other factors are adjusted.
Round about this time in the discussion, there comes the old nudge, nudge, wink, wink and the pearl of wisdom is dispensed that silencers don't work unless subsonic ammunition is being used. Trouble is, that's an absolute, and may not be all that relevant to what you are trying to achieve. In dry air at 68 T (20 TC), the speed of sound is 1,125 feet per second. Way above what a lot of handgun rounds are doing, but a .375 H&H isn't going to travel less than 2,500fps no matter what bullet you use from a factory load. And it will be pretty much the same for any heavy rifle cabibres. And this is where the technique of silencing a firearm of necessity involves a competent reloader if we're talking heavy bores. This is not who African poachers typically are.
Subsonic loads are still loud at the muzzle. A subsonic load travels at a low enough velocity so that it will not break the sound barrier. But a supersonic load will break the sound barrier with a supersonic crack somewhere in it's trajectory. Now, introduce the silencer. Shoot the subsonic load through a suppressor and the shot will remain "quiet", which is a relative term, because it will not produce that crack in flight. So if the entire shot is to be silenced, a subsonic load is pretty much necessary.
At this point you might be wondering (a) how to make a .375 subsonic, and (b) how much performance you will lose, but it's all moot--poachers don't employ sophisticated reloading techniques!
Once upon a time there was a bunch of idiots named Woods, Bawden, Smith, Maguire, and Conjwayo. They ran around Zimbabwe in the '80s planting bombs and causing other acts of destabilisation and terrorism for Pretoria. When they were caught, among other really cool toys, they were found with silenced--or suppressed (I am using the terms interchangably)--Heckler & Koch MP5 9mm submachineguns. I was also allowed to play with these on a couple of occasions, and they really were quiet.-just about all you could hear was the sound of the working parts as the guns cycled.
Sounds like a good excuse to spend some time on the range, right? A well-known PH just happened to have acquired a commercially-manufactured 'reverberation-forbearance contrivance' so we went out to play.
From a distance, the 'bang' with factory ammo would have been just that--though difficult to judge position or range from. The interesting part would be to see what it would do with a 500gr bullet at subsonic velocity. This was duly achieved with 19gr of Somchem's S265, loaded with a tissue filler. The result was 1040fps, and from distances of 50-100m in fairly thick bush, the result was recognisable as a shot, but a very muted one indeed.
Now to look at what such a load might be capable of. The muzzle energy of a 500gr bullet travelling at 1040fps is 1,201 foot-pounds. That's not all that impressive on paper--about the same as you'd get from a 55gr bullet out of a .223 Remington at just over 3100fps. A Taylor KO index of a little over five and a half. That works out to 1,63kJ, which in Zimbabwe would be legal for use on species listed in Part D of the Parks & Wildlife General Regulations--bushbuck, impala, reedbuck, sitatunga, bushpig and warthog. Even Selous' old 4-bore would have pushed out a 1750gr projectile at around 1300fps for a muzzle energy of 6,569 foot pounds. That would be legal on elephant even today in Zimbabwe.
So what's the point? See "a good excuse to spend some time at the range" above. Poachers don't reload, and if they did a subsonic heavy calibre wouldn't be good for much. But for an anti-poaching unit in the field, a silenced shot will be very difficult to place in terms of direction or distance, which is why more and more silenced heavy rifles are being recovered. And that is point enough.