paint ball guns are basically what your looking at, all the bits you need without the fancy outer shell that makes it look like a gun. Most airsoft guns even when not based on a real counterpart is going to be designed very much the same as any other rifle
I’ve held back on commenting with that.
Paintball guns really did evolve into a functional gun without the specific needs of dealing with an explosion inside & recoil etc
The common elements are the trigger & grip, and some form of foregrip (or something to hold steady)
Though there is no longer the physical needs of of a trigger mechanism striking the percussion cap, it’s ergonomic and performs naturally for the user. All we need now in Paintball or airsoft (obviously electricaly operated guns) is a switch, but it’s still more natural to pull a trigger and have it flick a rocker switch
A Paintball ‘speedball gun’ has gone down to the ergonomics of projecting balls as opposed to the physical needs of firing and absorbing the force of a bullet
The obvious ‘unique’ element in Paintball is the hopper feed. You shoot balls so they can just be poured in to reload. The only need for any special hopper as opposed to a basic hopper are either agitation to stop 3 or more balls sitting on top of the feed and ‘jamming’, or a force feed system to ensure enough balls are lined up for the rate of fire
As BBs are 6mm compared to Paintball’s .68” / 17mm ... (I was distracted earlier and didn’t end the sentence!) .... then the smaller ball could fit more balls lined up into a ‘stack’ ready for the next shot. Therefore there may not be a need for any forced feed system - putting something into practice would prove or disprove that
The less obvious is paintballs ‘ball stock’.
’Woodsball’ guns look like ‘real’ guns, because that’s what people think a gun should look like and that’s what they buy
When the air cylinder was added to Paintball guns people still added stocks and also tried to take off the cylinder using a remote line.
From experience people learn that a fibre cylinder with a curved base acts as a stock to steady your aim but also rotates in your shoulder to smoothly lift the gun to your shoulder or to adjust aim
(A Paintballer / gunsmith actually designed a similar stock for one of the British Olympic shooting teams. The stock was banned)
Finally it does not have to be offset to your side, pointing forward from your shoulder, which means you offset your head to aim.
Instead, angle the gun:
Cylinder in your shoulder, gun tipped, with the barrel in front of your face
You can also train your eyes for x-ray vision - place the body & line of the barrel between your eyes, each eye looking past either side of the gun, focus on your target.
Each eye can see a bit of gun and a bit of clear view, your brain sticks the two images together and you see straight through the body with a direct line of sight where your balls are pointing
Pistols are much simpler - we instinctively point. Put a pistol in your hand and you can point it on target even when firing from the hip