Suppressors are interesting devices which can expand the utility of your firearms, and protect your hearing. Commercial suppressors require a wait time of 8-18 months for BATF approval so the purchaser can take their toy home. Yeah, you pay up front for the cost of the suppressor and the Federal tax stamp, and then wait many months while YOUR suppressor sits in the NFA vendor's safe. However, there are alternatives.
You may have seen or heard about "solvent traps". These so called solvent traps are supposedly used to trap the run-off of firearm cleaning chemicals. In reality, many solvent traps can be the foundation of a suppressor. Last year I attended a relatively large gun show, and there was a vendor there retailing various solvent traps. First, all of the vendors stress that their traps cannot be modified in any way until the user has received a BATF tax stamp. I spoke with the vendor regarding his products, and he was very helpful regarding how the traps could be used with particular firearms. I didn't purchase at that time, but I followed up with some internet research.
A couple of months later, I encountered the same vendor at another gun show, and this time I made a purchase. I had a commercial .22 suppressor already in the BATF waiting jail, but I knew that I wanted another .22 suppressor that would be dedicated to a varmint rifle. So, I purchased an 8" tube, with seven baffles and an appropriate spacer for the blast chamber. In this case, one of the end caps was threaded for 1/2 x 28, and the other end cap was undrilled except for a dimple at the center. I also had the choice of either aluminum alloy baffles or stainless steel baffles. I went with a stainless steel baffle at the blast chamber, and aluminum for the six remaining baffles to keep down the weight. All of the baffles had a small dimple at their centers, which help the builder with drilling.
Before any drilling occurs, you must have an approved BATF Form 1 in hand. A BATF Form 1 is an application to build or modify a firearm, though it also applies to suppressors. Now the best thing about Form 1 is their relatively quick approval times. I received mine in five weeks. Hmmmm, five weeks versus 8-12 months...
Once I received the BATF tax stamp, I took the tube to a NFA FFL who laser engraved the tube with the name of the manufacturer (me), my city and state, the caliber of the suppressor, the model number and the serial number. The model number and serial numbers are determined by the manufacturer, so I made up a model number and a serial number, which is on the Form 1. The laser engraving literally took 15 minutes. Once the engraving was completed I took the tube home to commence the real building process.
A suppressor is actually a simple device. In most cases it's a tube with either a series of baffles or a monocore, which is a piece of metal that is shaped in such a way that it breaks up the sound "flow". The simplest was to attach a silencer to a firearm is to have the silencer end cap threaded so that it can directly thread onto a gun barrel, and that is how my Form 1 .22 silencer is configured. Next to the threaded end cap is what is called a blast chamber, which receives the initial blast and then funnels it through the baffles. The size of the blast chamber has a direct impact on how effective the silencer will reduce noise. A larger blast chamber means a more effective silencer. It's important for the blast chamber to be rugged and durable, since it receives most of the muzzle blast, along with propellant residue.
The rest of the tube is a series of baffles. which break up the sonic flow. These baffles redirect the sound in a series of mini-blast chambers. Each chamber reduces the sound level by a finite amount. A long silencer with many baffles is going to be more effective than a very short silencer. Silencer length does eventually meet a point of diminishing returns, where the extra length doesn't provide any further sound reduction. Extremely lengthy silencers also have a higher possibility of baffle strike too. My silencer is a little over 8 inches long, which is long for a .22 silencer.
Back to the building process... my silencer had seven baffles and an end cap to be drilled. From my research, I determined that a 9/32 bit would be appropriate for .22 bullet passage. The closer the tolerance to the bullet size, the more effective the silencer. In most cases, suppressor builders will overbore their holes by 0.06 inches, 0.08 inches maximum. This provides adequate space for the projectile to pass through and reduce the likelihood of a baffle strike. Baffle strikes usually occur when the suppressor isn't properly mounted to the firearm, the baffles aren't perfectly concentric, or if there's dirt or debris in the suppressor.
Fortunately, I have a floor mounted drill press at my disposal. The center dimples on the baffles and the end cap really simplified the drilling process. Each baffle was placed in a xy vise, which allowed me to precisely drill each part. The end cap was much thicker, but with the press, it was still an easy job. Drilling took less than an hour. The same job could be done with a table top drill press and a pair of vise grips substituting for the xy vise. I've seen videos of some builders using a jig and a hand drill to perform the same job.
I cleaned up the parts and then assembled them in proper order inside the silencer tube. The suppressor was then mounted to the intended host. At this point I used a guide rod to insure concentricity, as I was concerned about a baffle strike. A guide rod is simply a rod that is the same diameter of your intended projectile, I found mine at the McMaster-Carr website.
The guide rod passed through without impingement, so now was the moment of truth. The firearm was loaded with Aguila 40 grain subsonic cartridges. When the first shot was fired, you could hear the firearm striking the primer, it was that quiet. Even though I was using subsonic rounds, the sound of the bullets traveling through the humid air was still noisier than the actual shot of the firearm. Overall, I've found my DIY suppressor to be quieter than my commercial .22 suppressor.
The cost of the components was around $140.00. My Tactical Solutions Aeris commercial suppressor cost around $225.00, so the DIY suppressor is less expensive too.
It's been a learning experience, but well worth the time and effort. For anyone wishing to obtain a suppressor quickly, the Form 1 builder route is the way to go. I'm already contemplating a 9mm suppressor build for my next project.
The first photo shows some of the suppressor components prior to drilling, and the second photo is the finished suppressor mounted on its host!
