Hence the quotation marks. Assuming you could fire it from a space suit, the powder/oxidizer would create it's own pressure wave as it escapes the gun, if that wave/bubble hits your suit you should be able to hear something, but probably nothing you'll need hearing protection for.
Wherever the gas would escape from, as the gas "bubble" expanded, wherever/however it hit your suit, would vibrate it in some way as it impacted it. To speculate, you would probably hear a thump of sorts primarily from the ejection port side of your suit as the escaping gas hits it.
Hence the quotation marks. Assuming you could fire it from a space suit, the powder/oxidizer would create it's own pressure wave as it escapes the gun, if that wave/bubble hits your suit you should be able to hear something, but probably nothing you'll need hearing protection for.
Wherever the gas would escape from, as the gas "bubble" expanded, wherever/however it hit your suit, would vibrate it in some way as it impacted it. To speculate, you would probably hear a thump of sorts primarily from the ejection port side of your suit as the escaping gas hits it.