One of the things noticed when you start to use suppressors/silencers is the annoying first-round pop often experienced with small silencers, especially for .22 rimfire pistols.
For many silencers, the first round sounds noticeably louder than subsequent rounds. The first-round pop may not be much of a problem. On the other hand, the first round may be the round you wish to suppress the most.
It has been theorized the first round pop results from unburned powder flashing into the oxygen contained in air in the silencer. After the first round, the air with oxygen in the silencer has been replaced with gases from the first round.
People have found ways to reduce or eliminate the first-round pop. Some spray water into the back of the suppressor. Some have put wire lubricant gels into the suppressor. One product displaces the air with CO2. Another method is to fire a very low-powered cartridge, such as Aguila Super Colibri .22 through the suppressor. The Super Colibri is very quiet, and it eliminates the first round pop if the suppressor is used in the next few minutes, before atmospheric gases re-populate the inside of the suppressor. This effect can be prolonged by placing a piece of tape ( a half inch square of duct tape works well for a .22) to cover the hole in the suppressor. The other end is sealed by a cartridge case or a cartridge in the chamber. There are safety concerns with this method as you do not wish to place your finger over the muzzle of the silencer if the firearm is loaded. A tool, substituting for your finger, such as a tennis ball, can firmly press the tape in place without placing your flesh in line with the bore of a loaded firearm.
The tape method has been observed to work fairly well for 30-45 minutes. The tape is blown off by gases coming out of the suppressor ahead of the bullet. The point of impact does not seem to be affected at 15 yards.
About five years ago, Silencerresearch.com marketed a product called Ultraquiet Silencer Gel. It appears to use ultrasound gel but does not appear to be available anymore.
A colleague of mine, Jeremy S., wrote an article about shooting suppressors “wet” about two years ago. An ablative material inside a suppressor, such as water, foam, oil, or gel, uses up energy which then reduces the noise produced by the shot. Jeremy S. has experimented with using electrode or ultrasound gel to run a suppressor “wet” to reduce the first round pop and improve performance. Jeremy reported significant success.
Considering Jeremy’s success, this correspondent purchased some of the recommended gel, Spectra 360 Electrode Gel from Parker Laboratories. It was available from Amazon, a three-pack (25.5 ounces total) for $13.35. Only a small amount, less than 5 ccs, is used in a suppressor per application. The cost of the gel is a small fraction of ammunition cost and a tiny amount compared to the cost of a suppressor. Jeremy warned against using more than 5 ccs (cubic centimeters) per application. That amount can reduce the volume of the suppressor considerably and can be dangerous because the gel, unlike air, does not compress.
25.5 ounces of gel is 754 cc of gel. If one cc is used per application and is good for five shots, the cost per shot is about a third of a cent per shot.
One cubic centimeter is about the same volume as five .22 Long Rifle cartridges. Five cubic centimeters is about the same volume as 25 .22 Long Rifle cartridges. One application lasts approximately 5-30 shots, depending on numerous factors. A comparison of a bead of the gel to a .22 cartridge can be seen in the orange bottlecap in the image showing the gel and .22 cartridge boxes.
In a small suppressor, the volume of 1-2 .22 Long Rifle cartridges is enough to reduce first-round pop or later shot noise for 3-5 shots.
The gel is applied to the expansion chamber at the rear of the suppressor. Do not block the bore of the suppressor. Blocking the bore could deflect bullets, and destroy the suppressor. It is unsafe.
The gel is very, very sticky. It is easily removed with soap and water.
This correspondent verified what Jeremy S. determined. Being able to duplicate results is a basic part of science.
The use of the gel reduces the perceived noise of the “first round pop” significantly. Sometimes, the second, third, or later rounds sounded louder than the first round. The gel has the salubrious quality of making suppressor clean-up easy. It is water soluble. As it is a gel, it tends to stay in the suppressor for a considerable period, at least for several days.
The gel appears to work the best in small suppressors, which appear to need it the most. The effect can be prolonged by placing some gel in between baffles if you can easily do this. Shots appear to distribute the gel fairly evenly. The gel disappears from the expansion chamber at the rear of the suppressor first. It appears vaporized or liquefied gel is gradually ejected out the muzzle of the suppressor, carrying fouling with it.
The gel has become another tool in this correspondent’s ability to shoot without hearing protection.
Jeremy S. Tested centerfire pistol cartridges. This correspondent tested .22 rimfire cartridges in pistols. Your results may vary. AmmoLand would be interested in what others learn about this technique.
About Dean Weingarten:
Dean Weingarten has been a peace officer, a military officer, was on the University of Wisconsin Pistol Team for four years, and was first certified to teach firearms safety in 1973. He taught the Arizona concealed carry course for fifteen years until the goal of Constitutional Carry was attained. He has degrees in meteorology and mining engineering, and retired from the Department of Defense after a 30 year career in Army Research, Development, Testing, and Evaluation.