How much noise does it makes?

Some technicalities are in order first.

Sound is measured in decibels (db), much like temperature is measured in degrees and speed in miles (or kilometers) per hour. Like most other units, the bottom of the scale or 0 db, is an arbitrary setting, which by convention is set to be the level of the sound that we can bearly hear, or our hearing threshold, as it is normally known.

One difference between the decibel scale and most of the other units we usually use in our everyday life, is the fact that the decibel scale is not linear, but logarithmic. In a linear scale, like velocity, if someone's car is moving at 100 mph, we know that he is moving at twice the speed of someone else who is doing 50 mph, i.e. 2x50 mph is double the velocity of the second car. In logarithmic scales a sound which is only 3 db higher than another, has twice the energy. For example, if you look at the table below, the 9mm Para cartridge at 160 db has twice the sound energy of the .45 ACP cartridge which is measured at 157 db.

Another complication is that the human ear does not hear linearly either. Although loudness is subjective, most people perceive one sound to be twice as loud as another, when there is a 10-fold increase in energy, or a difference of about 10 db. So a 60 db sound sounds twice as loud as a 50 db one, although there is 10 times more energy in it. Also, it is interesting to note that most people cann ot discern any difference in perceived loudness of less than 3 db. That means that the energy in the sound has to double, before someone can notice any difference.

After this technical jargon, here is a table of loudness.

No wonder why the damn Glock sounded louder than my Bigmouth at the range!