Test Report - GMS suppressors

I refer to the test report on GMS Suppressors in the September/october 2020 edition. While there is little doubt that the product is excellent, some aspects of the test are questionable and others, interesting.

A reduction in the muzzle blast will certainly be noted but to claim it is suppressed by 75% is unquestionably wrong. Relative sound pressures are measured in decibels (db). The upper threshold in the human ear is called the onset of pain. It is about 120db above the lowest detectable level for hearing which is the zero reference. Absolute numbers cannot be put to these limits because the minimum sensitivity starts to weaken at a young age. The convention for the human ear is 120db. This is a huge number and a miracle of the ear’s physiology.

Decibels are a logarithmic scale, so a 120db range is a one-million, million to one (12 noughts) difference in sound pressure! The sound pressure near the muzzle of a .30-06 rifle has been measured at 171db. Reducing these levels by 75% with a suppressor of any sort is not possible.

It is interesting that reduced recoil was noticed. A suppressor is unable do this – other than by adding weight to the rifle. However, this would be too small to notice. It could be a perceived change by altering the balance of the rifle even if it is at rest on an X-bag. If the suppressor were ported it will arrest some of the recoil but in so doing, it would significantly increase the muzzle blast. Guns with muzzle ports are sometimes prohibited at shooting ranges due to the excessive blast experienced by fellow shooters at the firing point.

Improved accuracy was another interesting observation. It is most likely due to a change in the barrel resonance and not to the gas dynamics of the suppressor. Barrel resonance is a condition often overlooked.

Some readers may disagree with me, but I feel an eight-year-old youngster is too small to be shooting a 7x64 Brenneke with its recoil energy of 46ft.lbs and a recoil velocity of 17fps. Despite the boy’s enthusiasm, this is too much for him to handle and may be the root of flinching problems in the future.