I've heard there are earphones which can filter out loud noises while passing through voices and shit
What you are describing are known as Active ear protection, Various models are in use with Conventional Forces, Special operations groups (Delta Force, SEALS, Army Rangers, JTF2, the list goes on) and tens of millions of civillian gun enthusiasts. They do in fact filter out (or "remix" to be hearing safe in some cases) noises over a certain decibel range (gunshots, explosions, the roar of jet engines). Various manufacturers make various models with different features and price points, ranging from the Howard Leight Impact Sport and Walker Defense Razor's (which can generally be found for less than $100 but have less than Ideal sound performance, that is things sound less "natural", like $30 generic brand gaming headphones) to MSA Sordins or Peltor Comtacs ($4-800 depending on model, much better sound performance, can even tune them in some cases to give you an enhanced sense of hearing (that is, you can pick up noises that would likely be imperceptable or of indeterminate origin and have a better chance of classifying them), have various options for radio integration and some of the more expensive Peltor models even have this weird thing where it can wirelessly communicate with other Peltor headsets of the same model without the need for keying a radio up to like 30 feet or something) and then you have things like the Ops Core AMP series that goes for $1k Minimum.
Headsets can also be integrated into many models of helmets assuming they have the proper mounting hardware, Headsets can also be worn under helmets with various levels of comfort depending on the band configuration of the headset (whether conventional or a "neckband" model) and padding arrangement in the helmet.
TAC Progressive trigger system for M16 Rifles, pull back a little for semi auto and all the way for full auto
Carbon-15 SBR
Pengun made from 10/22 barrel
Folding Bullpup SVD (SVU?)
Trailblazer Firearms Lifecard with Enhanced Systems Sidewinder Grip module that allows for the attachment of a FAB Defense Cobra stock. The grip module also includes a trigger guard pic rail attachment, The silliest SBR.
Prototype Suppressed .22 Bullpup, is a gun, possibly the most integrally suppressed gun.
Dalphon .50AE Conversion for AR's
The bolt lugs extend forward past the bolt face for some reason
Features the most primitive adjustable gas system imaginable, a "master" hole is drilled into the barrel and you can swap the gas block around to make two holes of different sizes line up with in, one is for standard pressure and the other for +p
Magazine