I received an e-mail from a reader requesting some information on wipes. I apologize for that omission. In modern suppressor designs they are the exception and not the rule but it does merit discussion.

A wipe is a replaceable baffle usually made from a polypropylene or polyurethane material. These disks can be placed at any point along the length of the suppressor but are generally found closer to the exit point where gases are at a lower pressure and temperature.

When the weapon is fired, the bullet punches through the wipe exiting the suppressor on its way down range. The perforation made in the wipe exactly matches the bullet’s diameter creating a reasonably tight seal adding considerable resistance to the propellant gases. The wipe is usually good for 10 or 20 rounds, no more than a magazine or two, then it had to be replaced.

The best way to illustrate a wipe is to show you a cross-section of the U.S. Navy’s Hush Puppy – used extensively during the Vietnam War.  I’ve marked it up to show what the propellent gases are doing.

US Navy Hush Puppy Cross Section (wipes are blue disks)

Because the bullet punches through a solid disk, manufacturers prefer that users restrict the ammunition used to ball; avoiding the use of hollow points. The reasoning is that wipe material would fill the hollow point and adversely affect its terminal performance. I am have my doubts about that; however, the possibility of premature bullet expansion does exist. You can avoid this by using a wipe that’s be punched for the bullet diameter.

Some modern designs like the DeGroat Tactical Nano offer the opportunity to install a wipe at the exit point or suppressor muzzle.

When combined with modern suppressor designs the wipe does add a level of attenuation. I’ve not measured that performance but in my subjective assessment it provides a level of attenuation as well as lowering the characteristic resonance of the suppressor. High frequencies are highly directional, so any time you can dampen a higher frequency signature it’s a positive – in this writer’s mind.