Originally Posted by iNoob
Those are two of the three available weapon systems. The third is spring action, requiring for you to compress the spring yourself in order to power it. The last is usually the most reliable and requires the least amount of maintenance.
2 of the 3 main options.
There are also NBBs (non-blow back) Gas guns without blowback
and AEPs (Automatic electric Pistols) Kinda self explanitory