SoundGear has been at the NRA conventions. There's also the Sport Ears Ghost Stryke/Ghost Stryke II and Silynx Clarus Pro. An interesting workaround is the pair the GunSonics! app with a pair of properly fitted IEMs.
I'd also note that in-ear protection alone is generally considered inadequate for louder noises, though I do not know the threshold, due to bone conduction issues. Best practice would be to double up, either way.