New to AEG Gearboxs JG / SRC Comparison

Ok so I've always left the AEG stuff to others (more of a gas / spring person) but I've recently grown sick of bringing it into the shop and then paying $20 labour fees every-time.

These are the two GB I have one is from an SRC M4 where the trigger is locked up and I really don't care for it and the other is a JG reinforced black type GB from my Mk18 Mod0.

The SRC Gb was shooting idk what because its been broken for the past 2 years, something about a tappet plate. I have a feeling it was shooting 360Fps.

The JG is currently shooting 22Bbps at 280Fps. But it occasionally skips to full-auto when its on semi.

My question is what should I take from the SRC Gb and replace in the JG Gb.













I saw that the anti-reverse latch on the SRC is one solid piece whilst the JG one was 2 seperate peices.

Honestly I've never touched let alone opened an AEG so please bare with me I'm really just looking for parts to exchange between the two to make one of them run very well at around a 350Fps configuration.

I do have a spring that was shooting 425Fps on hand could I cut that down to run at 350Fps?

Also would the SRC or JG Gb be better to use as a shell.

Thanks in advance.