In real life, the G36 and the HK 416 are very close since the HK416 took the piston firing mechanism of the G36 and incorporated it into the M4 style body.
Also, there are two versions of the SCAR - L (light - 5.56 NATO rounds) and H (Heavy - 7.62 - like the AK47) in real life.
In KF, the SCAR packs more punch than either M4 or Bullpup, is close to the AK47 with a higher firing rate thus I think the SCAR is the H variant in this game.
You should balance the G36 to be faster than the M4 (old US variant) yet pack the same or slightly more punch than the M4 , but not at AK47 or SCAR levels due to the kinetic energy difference of the bullets.
I would make the G36 more accurate (less recoil), faster firing rate, cost a little more, but be nearly equal in power to the M4. That would make it a balance gun and still keep the AK47 (high recoil, lots of power) and SCAR (fast fire rate, lots of power) still balanced.
If you make the G36 expensive and high power, there is no need for the AK47 or SCAR. In real life, the G36 does not have the same power as either AK47 or SCAR-H. It is chambered for 5.56, not 7.62.
You can make a G36 with Beta C mag (100 rounds), add 1 more weight to it (for the high capacity magazine) and still keep it balanced. Just add another 1000 to it to convert it into a LMG.
The Russian Made 246 SAW can be the heavy variant of it.