Well, it is interesting to know that we live in a constitutional republic and that said republic has really interesting laws that govern some unusual things. One of those things is silencers, you see, a silencer is a muffler, nothing more…nothing less. These specialized mufflers are used to tame the sound and recoil of firearms to more manageable levels. The reason, I believe, that these safety devices are regulated so heavily comes down to congress being uninformed as to what a suppressor is at all. 9mm suppressor design follows the intent of these laws in a sense and because the laws are so strict on ownership, the USA uses vastly different materials in their silencer designs than most other industrialized countries around the world. Let’s take a short look at some of these materials and how they perform in the silencer role.
Aluminium
The first material that is used in a 9mm suppressor is good ole aluminum. Yep, both 6061 and 7075 have been used in 9mm suppressor designs in the past and with great effect. The 9mm suppressor generates fairly low muzzle pressure so it lends itself to this wonder metal really well. The typical 9mm suppressor that is built with aluminum will weigh in at around 10 ounces or maybe less depending on the design and will usually perform really well. We have made silencers in the past like the Miranda and the Patriot out of aluminum and even some of our specialty cans like the Uzi LS were even made from it.
Stainless Steel
The next metal on the list is usually stainless steel. This metal also is in common use in 9mm suppressor designs but it is also heavier and more costly than aluminum comparatively. This typically will make it a more specialized design such as a submachine gun silencer or, in more recent times, a multi purpose silencer. This category though is really pretty broad and runs into several grades of stainless steel, typically separated into two main camps, the 300 series stainless steels and the 17-4PH variants.
The 300 series is basically any of the metals in this class, such as 303(18-8), 304, or even 316 stainless steel, these are all great for 9mm suppressor use, but of these 303 is not really suited for welding. If you want to weld a 300 series silencer, then use either 304 or 316. The reason 303 doesnt weld very well is because of the addition of sulphur to the alloy. The sulphur is added to make the metal easier to machine when turning out shapes in the lathe or mill.
Better Stainless Steel
When it comes to 17-4PH stainless steel, there are several grades as well. This main ones used in 9mm suppressor designs is either annealed, H1050 or H1100. The annealed version is the softest and is designed to be machined then heat treated once cut to shape. The main thing with this is that even the annealed 17-4PH stainless steel is over twice as strong as the best 300 series stainless steel. This is one of the reasons why it is a favorite of the silencer world in the USA. Now the main problem with 17-4PH is the cost, it does cost more than 300 series stainless steel, so there is a trade off here. Do you need the extra strength of the stronger metal or will the 300 series do everything you need. In most 9mm suppressor designs, the 300 series will be just fine and will last many lifetimes.
Exotic Alloys
The last category is the exotic metals. Some 9mm suppressor designs are made from things like titanium or even other metals like inconel or some such as that. We use titanium in our Infiniti X 9mm suppressor for the main benefit, weight reduction. The strength of titanium is so great when compared to the weight is phenomenal. If you need a 9mm suppressor that is the absolute lightest as well as the strongest, then titanium if your metal. We rate our Infiniti X silencer for 300 Winchester Magnum, it is that strong even at the paltry weight of 7.7 ounces! That is the magic of titanium!
So I hope this clears up some of the questions about what metals are used in making silencers in the USA. Till next time, keep your powder dry!