Are Piston semi-autos hearing safe at ear?

[savagetactical]

Guys,

I know AR-15s in 556 are not hearing safe at the shooter's ear because of the noise coming from the ejection port. Is the noise coming from the gas being expelled from the gas tube or is it coming from the chamber? Assuming the majority of the port noise is from the gas tube, would a piston driven gun like a SCAR, FAL, or TAVOR be hearing safe at the ear or at least quitter than an AR DI system? What about a roller delayed blowback system like on the HK91 or HK93? Are those rifles hearing safe at the ear suppressed since they don't use a gas system at all?

[poikilotrm]

All firearms will damage your hearing. Wear ear protection. A suppressed weapon is still loud.

[JasonM]

port noise is from any and all gas escaping rearward.

Piston guns have plenty of gas escaping out of the chamber once they unlock, any sound decrease from not having a gas tube is made up for by the extra noise coming from the gas block/piston where the gas escapes. In my experience, piston guns are louder than DI guns suppressed, even the ones with "suppressed" setting on their gas blocks.

Same with roller-delayed guns... pretty loud.

There's no free lunch, and there's no hearing-safe semi-auto rifle (with supersonic ammo).

[TROOPER]

I know AR-15s in 556 are not hearing safe at the shooter's ear because of the noise coming from the ejection port. Is the noise coming from the gas being expelled from the gas tube or is it coming from the chamber? Assuming the majority of the port noise is from the gas tube, would a piston driven gun like a SCAR, FAL, or TAVOR be hearing safe at the ear or at least quitter than an AR DI system? What about a roller delayed blowback system like on the HK91 or HK93? Are those rifles hearing safe at the ear suppressed since they don't use a gas system at all?

Where does the gas from a piston-driven platform go? The gas is expanding behind the bullet... then is bled out of the barrel in order to punch/push a small cylinder-rod back, which taps-or-strikes the BCG. Ok. So where does the gas go? After doing all of the above, does it flow back into the barrel and then exit the muzzle? Is there any extra gas being ejected into the BCG at all? Or does any fouling that end up in there get there after partially ejecting rearward via the chamber?

I know basically nothing about ARs, whether it be DI or gas-piston.

[T-Rex]

Don't forget the bolt is a solid, metal, reciprocating mass.

I made an integral 22lr on a Ciener kit, in an AR15.
You can't hear the ammunition, at all, but the bolt noise is disappointingly loud.
And that's a much smaller piece of steel.

[Joshua@CapitolArmory]

My piston guns are just as loud to my ears (haven't metered them much) as "DI" guns. The Tavor we shot was loud to the shooter, it sounded (to me) quite a bit more harsh than an AR.

On my piston AR, I can turn the gas off and just have it as a single shot. That quiets it down a substantial amount, but it's no longer semi-auto.

[JasonNC]

I've shot my Tavor with a YHM Ti Phantom without hearing protection a few times but its not something I would do often. Now I will shoot one of my .45 ACP pistols with my Osprey on it without ears on without hesitation. Same of course with all my rimfire cans.