Hey! I think it’s a very nice synthezied a blast, but I wouldn’t say it sounds realistic. I would leave a slightly longer tail (3 or 4 seconds), prepare 3 or 4 variations (thinking of a potential video game usage) and name the item “Retro Game Shot” or something like that.
Actually I might even use a bit crusher and include some lo-res 8 bit versions.
For a more realistic approach I might leave your asset as a layer, include a fairly close recorded firecracker pitched down and definitely add metal sweeteners, like keys, chains, and that sort of stuff. I normally use an old horse bit I found on a flea market, but anything could do the trick.