Combat Machine Internal Upgrades
 

What are the "bang for your buck" internals for my gun? I'm not really wanting to spend $100 at the moment
Currently I'm going for maybe 15+ RPS and 400-420 FPS Build
(Not looking into getting a MOSFET)
What I need first is a high torque motor and spring, should I upgrade the piston/head?
What gears should work best for my build?

P.S Gun is completely stock.

Hopup unit

I disagree, the combat machine come with a very good hop up unit. if you don't want to spend $100 - maybe better quality bbs

I replaced the Hop up with a Pro Win and added a PDI w/ Hold bucking. The air nozzle, piston and cylinder heads were replaced with Lonex and my seal and accuracy are much improved over the stock parts. I still have to determine the range limit but I estimate I'm accurate to around 200 feet.

How much in total were the parts? not including the hopup unit.

Less than $60. Bought them from Stealth.
Lonex Aluminum Cylinder Head for Ver. 2 $16.50
ZCI M4 Nozzle with O-ring $6.60
Lonex POM Ventilated Piston Head $18.70
PDI W-Hold Chamber Packing for AEG $15.00

air seal components and the pdi w=hold will bet you better results than just changing a hopup unit. Most of the time it's the rubber and how it's installed, not the unit itself that leaks.

have you taken it apart to see what your compression is?

with your goals, a hop up unit will not help you get 15+ rps or 400fps.

If you are budget limited, stick to the basics to improve the elements you want to improve first. If you open the gearbox now to do a spring swap, it makes most sense to do all your internal gearbox work now.

15+ rps can be achieved more than likely with the lonex a5 motor and more efficient wiring and a shim job.

While you are rewiring it, a mosfet makes the most sense, it's only a 30$, spring 15$, a5 motor is 32$, if needed, piston head, piston, sorbo and cylinder head are 46$ all together. pdi w hold is 14$.

Out of that list you can drop the mosfet, but it saves you money long term with not having to open your gearbox to replace trigger contacts. It makes sense to do it. It's a basic fet, not a computerized one with special features. It will also help raise the RoF.

Most motors on stock gears should be able to get 15 rps with a 9.6v nunchuck, mosfet and a good shim job.

Thanks for the advice but I'm a total newbie to airsoft internals. I have a little knowledge about MOSFETS but not how to make one, what materials I need, how to solder, etc. If I were to give it to one of the airsoft retailers in my city, he'd charge me 25/h which i'd rather much save on upgrading the gun even further.

Also, would I need to change my gear ratios?
And is there a certain site that I could purchase there parts off of without having to go to big airsoft retails such as Evike or ASGI, because their shipping prices with UPS are ridiculous

*coughairsoftmechanicscough*

best upgrades you can make to a stock gun: shim via bevel/pinion, sorbothane pad, rhop. other small tricks can be learned along the way.