[MadMax]

I've had a chance to see this device at ShotShow where Simon was proudly showing it off.

It's really nicely made and the report is pretty good. It didn't seem too damaging. I've heard dryfiring paintball guns which sounded a little harsher. The GSG-01 offers a sharp pop that I wouldn't consider to be overly damaging.

I do note that the Youtube vid showing the dB measurement had the grenade pointing right at the meter microphone at a very close distance (around 5cm when it went off). 125dB is a high noise intensity, but a distance of 5cm is very close for noise measurement. In open air measurements, dB decreases by 6dB for each doubling of distance.

The standard for most equipment noise measurement is 3' (IRC...) which is about 90cm which is 18x further than a 5cm measurement. I'm not sure how the applicable it is to reduce by 6dB for doublings from closer distances like 5cm, but if it applies well, a measurement at the standard 3' distance would come out at under 96dB (18x is greater than 4 doublings of distance 2^4=16).

At 5cm with the opening pointed at your face, the GSG-1 is a bit louder than a car horn at 3' or the racket at a rock concert. At 3' the bang exerts similar sound pressure to driving down the highway with your top down on your 'stang. I have no idea about the directionality of the GSG-1. It's got one exit port so I suspect that it will have some aspherical intensity distribution.

Properly specified dB intensity ratings should be stated with the measurement range.