Recent testing by the FBI and the US Army has shown that the 5.56 NATO round may actually be safer for use in CQB environments. The theory being that the lighter bullet of the 5.56 NATO round sheds energy MUCH faster in common building materials like sheetrock and 2x4's. Recently our own testing showed that although the results look somewhat promising for the 5.56 NATO round as far as some penetration tests, there are some very significant long term dangers to the LEO who may be behind that gun while doing a dynamic entry.
In our tests the 5.55 NATO round (M855) fired out of a Sig 552 rifle posted 163dBs. With a suppressor that same round posted 128dBs*, still WELL beyond the pain threshold and certainly well beyond the OSHA standards of 85dBs. Since most SWAT teams tend to train with hearing protection but work with none, this can have long term effects on each members hearing. Also of concern is the immediate threat to an officers hearing (3 rounds will do permanent damage) and how that effects command and control of a situation.
From a tactical perspective, many have tried subsonic 5.56 rounds to little or no avail. They are generally less reliable, less accurate unless shot via specialized barrels, and essentially about as powerful as a rimfire rifle when brought down below subsonic speeds. The reason the 9mm and .40 S&W are so popular is that they KEEP energy and have good terminal performance when going subsonic. (Good for hearing, good for taking out the bad guys, but bad for over penetration)
There are several solutions that are up and coming including in ear "bone" mikes with built in hearing protection, newer helmets that allow for the use of miked hearing protection, and even a full helmet system similar to those worn by motorcycle riders (remains to be seen).
In any event, as you train or work, keep in mind your ears are essentially the only pair you get and there is no real cure for hearing loss, only patch fixes. If you start having problems hearing seek medical attention as soon as possible, continued exposure to loud noises will not be "fixable".
* (by comparison a chain saw is about 120 dBs)
In our tests the 5.55 NATO round (M855) fired out of a Sig 552 rifle posted 163dBs. With a suppressor that same round posted 128dBs*, still WELL beyond the pain threshold and certainly well beyond the OSHA standards of 85dBs. Since most SWAT teams tend to train with hearing protection but work with none, this can have long term effects on each members hearing. Also of concern is the immediate threat to an officers hearing (3 rounds will do permanent damage) and how that effects command and control of a situation.
From a tactical perspective, many have tried subsonic 5.56 rounds to little or no avail. They are generally less reliable, less accurate unless shot via specialized barrels, and essentially about as powerful as a rimfire rifle when brought down below subsonic speeds. The reason the 9mm and .40 S&W are so popular is that they KEEP energy and have good terminal performance when going subsonic. (Good for hearing, good for taking out the bad guys, but bad for over penetration)
There are several solutions that are up and coming including in ear "bone" mikes with built in hearing protection, newer helmets that allow for the use of miked hearing protection, and even a full helmet system similar to those worn by motorcycle riders (remains to be seen).
In any event, as you train or work, keep in mind your ears are essentially the only pair you get and there is no real cure for hearing loss, only patch fixes. If you start having problems hearing seek medical attention as soon as possible, continued exposure to loud noises will not be "fixable".
* (by comparison a chain saw is about 120 dBs)