Could you build me a 35-40 rps gun? Would you just be building the GB or would it be cheaper to buyou an entirely new gun?

Oh this thread is ripe with good reads :)
RPS isn't a goal most real airsofters aim for. My Z Custom build is north of 30 rps but I never run it in full auto and in fact both Semi and Full are locked to semi only now. The rps is a by-product of a snappy as fuck trigger which is what I wanted.
Honestly, you are in for a world of hurt and my advice is to do some research before you continue posting.

Yeah. I guess if I'm playing CQB, I don't need that much rps! I love instant trigger responses so that's what I think I'll do. I'll drop the fact that 30-40 rps is too much and focus on good internals and a great trigger response! I also have experience problems with semi auto not firing when I need it to. It locks up and I have to shoot on auto to "unlock" it. Do you have any problems with this?

Even with stock guns I never had an issue with semi lock. But YMMV.
I have a lot of money in my GB. If you want something with instant trigger response and quality reliable parts its not going to be cheap.
I am sure I could eventually figure it out myself but the good techs have tons of hours and solid builds under their belts that I just pay them to do it for me so I don't have to worry.

tienly 30k motor
SHS 13:1 gears
SHS metal rack piston

36rps

It's really easy to get the rps you want, the real technical part is making it work reliably, which is mostly just shimming, air seal, and doing your AOE.
I've got my M14 shooting 36rps and feeding .36s no problem. But I also put about $300 of parts in it.

Understandable. Could you give me a list of what's in your gun and what you've done to it? That would be great but if you don't want to, I totally understand! ;)

If I used .20 or .25s with an m110-130, would that give me a higher rate? I'm guessing since your using .36s, that your shooting in the high 300s fps?

I dunno, sounds like we have someone here that just wants to cause people pain.

60 RPS at 400+ fps? Jesus fuck. You sound like that guy that wanted to put lipstick on his knives so when he slashed peoples necks there would be "blood".

I would watch out for this guy.

And you want to shoot 60 rounds per second?

Where the hell are you playing so I can stay away from there!

I'm sorry, but that is ridiculous and a safety issue IMO

Pesto, I'm not claiming to be an uber leet expert however my advise was sound. To go 40+ rps is not simple and would need high end parts and stuff will break and it'll take time (ie money the op says he doesn't have) to achieve. To hit 30 ish rps (or i guess with a bit more shiming skill and the newish 12:1 gears I just googled) then I guess the 35-40 is just as easy with the exact parts I listed. Simplified a good compressions system desired spring for fps. A fet and good battery and a decent motor. The other advice was basically going 60 rps was a DSG (i still don't think 60 rps is being done on a ssg at 400 ish fps but I guess someone may have)
Also prety sure I didn't say I was an expert and suggested my knowledge was limited to building my own 30 ish rps guns, all of them basically built on the same base. 13:1 gears. A high torque motor on high fps and high speed on my 300fps indoor gun. A good piston (with some lightening) piston head, cylinder parts etc.
Not picking a fight, a lot of what I know is from reading post of yours often in response to my own questions on a build, I just don't feel I've given any bad info. Tried to discourage a 40 or 60 rps build. Suggested a budget 30 ish rps build that even a laymen like me can build and run reliably....
I personally have never tried to achieve 30rps by simply swapping the motor and battery and a fet because I figure lack of stock aoe correction will just shred teeth super fast and then require a rebuild anyhow. To me that's not any type of build at all and something a crappy shop would sell someone as "an upgrade"
Edit: I guess my crappy sentence structure and big blacks of text may make it hard to understand sometimes I spose.

Using a heavier bb is not the factor. Velocity is measured with a .20 no matter what. After that you can use whatever bb you want. The springs will increase the velocity heavier spring is harder to pull and is gonna need more work to run reliably and rps will be sacrificed for fps to a degree. A .36 bb at 275 fps is over 500fps on a .2 that's sniper rifle territory.
Using a heavier bb reduces the initial velocity but the energy is the same (sometimes greater) st the muzzle and the effective range is greater but that's a whole other conversation covered in depth in the stickies on this forum.

If all you want is instant trigger response get a gas blowback gun. My KSC MP9 has high ROF and instant trigger response, no tweaking required.

I would like to know what cqb field allows 400fps.

Shoots 1.4j on both .20s and .30s right now, so no joule creeping at all

With the 30k motor, it's a true torque motor, so you're hitting peak rpm on an M90 and M120. So shouldn't see much of a change in RoF if any at all.
Motors will load up to a certain amount of torque/amperage before they start slowing down, and consequently start to consume exponential amounts of amperage to keep trying to spin up to peak rpm.

That being said, the more torque you load on the motor, the more amperage is gonna go through, the faster it'll wreck your brushes and comm. Which is why running 60+rps is just silly on an AEG.

Unfortunately a lot of fields. Around here every CQB field has moved to 400fps because the new guys are just way too lazy to downgrade.