[mrFonzie]

Hi everybody I'm planning to create a DMR AEG using as base a G36C ebb specna arms.

Goals' project are:

1. To be more realistic as possible (so for this the ebb and not a high roof)
2. Silent
3. Reach long distances at 1j with 0.30g bbs

Here is a list of part that I'm thinking to use:

What do you think? Any changes?

My principal problem, for now, are the internals: I'm thinking to use a very tight inner barrel, helical gears, a full cylinder, a weak spring with a full run of the piston, ball bearings, a high torque motor, and a light piston to reduce the sound.

By the way, this is the first time for me that I use helical gears and I'm wondering if some of you can give me any suggestions about them and if please can explain to me the difference between 100:200 and 100:300 gears: I planned to use 100:200 for have a better trigger response.

I'm very indecisive on motor and gears and bearings:

1. Is basilisk a good and silent motor?
2. Helical gears work well with ball bearings sets or would better to take full bearings?

Thanks in advice :

 

[Akami]

You might want to go for a bore up cylinder set, and you don't really want to go for helical gears. They need extraordinary shimming skill, and while they make your motor could (a bit) easily pull stronger spring, most neodymium motor solved that problem. Helical gears was made when the motors are still using ferrite magnet. Your 1j build won't ask for an extra strong spring after all, except if you really want to take that extra shimming time to get more quiet operation.

Though with standard gears you could also achieve very quiet operations with correct shim and installation.

Anyway what i'm trying to say is, for your build list i think going for helical are a waste except if you want to get a bit more silent, and for the motor you could go for brushless motor so the operation could be quieter than standard brush motor.

Going for a tightbore barrel? That's a good decision. But try to consider using wide bore like orga 6,23mm since they could give extra range in cost of fps reduction, possibly a great pair if combined with a bore up cylinder.

Other than that i think it's mostly fine. I can only advice this much since my experience with aegs is rather shallow, someone with more experience in AEGs should be able to helps you further.

 

[mrFonzie]

You might want to go for a bore up cylinder set

But I could install it in my AEG without any big modifications?

Btw helical can go with ball bearings?

 

[mrFonzie]

You might want to go for a bore up cylinder

I don't think I can because is ebb

 

[Akami]

Right, i forgot about that point. Maybe you'll need a little modification, maybe a lot, idk. Try to wrap the standard cylinder in a thin aluminium sheet (like cans) to simulate a bore up cylinder, if it goes well then you can get a bore up cylinder.

About the helical with gear bearings, they can but i would prefer to use bushings since with helical your gearbox will experience load in both x and y axis (another reason why i don't like helical), possibly making shim wear and tear more frequently so you might need to perform maintenance in a faster cycle.

 

[mrFonzie]

Right, i forgot about that point. Maybe you'll need a little modification, maybe a lot, idk. Try to wrap the standard cylinder in a thin aluminium sheet (like cans) to simulate a bore up cylinder, if it goes well then you can get a bore up cylinder.

About the helical with gear bearings, they can but i would prefer to use bushings since with helical your gearbox will experience load in both x and y axis (another reason why i don't like helical), possibly making shim wear and tear more frequently so you might need to perform maintenance in a faster cycle.

By the way differences between gears 100:200 100:300 what are?
300 are more silent or at a level of sound doesn't change anything?
what is better for me for your opinion?

 

[mrFonzie]

Right, i forgot about that point. Maybe you'll need a little modification, maybe a lot, idk. Try to wrap the standard cylinder in a thin aluminium sheet (like cans) to simulate a bore up cylinder, if it goes well then you can get a bore up cylinder.

About the helical with gear bearings, they can but i would prefer to use bushings since with helical your gearbox will experience load in both x and y axis (another reason why i don't like helical), possibly making shim wear and tear more frequently so you might need to perform maintenance in a faster cycle.

By the way the main differences between 100:200 and 100:300 helical gears? Is it one more loudly than the other one? For you which one is better for my purpose?

 

[Skara]

So you want a "silent" replica but at the same time you want a slab of metal that reciprocates (creating unnecessary noise and stress)...

Okay.

That piston body is NOT fit for purpose, you want to have some mass for "heavy" bbs.
That cylinder head is trash, the plastic stock one is infinitely better.
Cylinder is oversized, iirc the G36C uses a 229mm inner barrel, the standard 3/4 hole is plenty.
Aluminium compression parts are generally shit, all the stress and vibration is transferred directly onto the gearbox shell, and while V3s are generally much stronger than V2s, in the long run you'll still crack them.
I have the same piston head in one of my M4s and the "improves sound reduction" part is purely marketing, the sound report was exactly the same as with the stock piston head.
Can't comment on the motor, but if you want a somewhat quiet, high torque, cool running motor then a ZCI 22tpa is what you want. I have two Warheads and while they run super cool, they are just as noisy as a SHS HT motor.
You don't even need torque gears, the standard 18:1s are perfectly serviceable to pull a M100 spring. You can even knock a few teeth off while still retaining the full useable cylinder volume and have a shorter stroke (less time for the system to create noise)

From personal experience a wider bore barrel (anything larger than 6.05, by today's standards) yields better consistency than a tighter one.

Shimming needs to be perfect, you need to take the time to eliminate any binding from the piston, tappet plate and all moving parts, which requires experience to do so.

You didn't mention the hop setup, only that you're going to use an Omega tensioner, and it's giga lame as the hop plays a crucial role in getting BBs over there consistently.

And again, I don't see the point in chasing sound suppression when your replica has a (shitty) mechanical blowback gimmick.

 

[Cripplegunner]

I have completed two projects converting two basic models of CYMA : CM513 & CM 518 . They're slightly different than your platform but the basics are very similar . Every one of my projects has swallowed at least 400 $ each. ( never count money spent on my hobby ) . The 518 reached 3,2 Joules , and 513 have stable 2,2 . The parts I've replaced were important on my view . In the gearbox I throw away 18:1 gears and replace them with torque max 32:1 - it reduces significantly the ROF but that's not so important for an DMR platform as it is still greater compare to BASR's Also I've replaced the 30K & 40K high speed brushed stock motors with brushless max torque ones 17K and 22K. All compression elements made of plastic I've replaced with metal ones with extra seals : from the spring guide to the nozzle . the stock shitty hops gone to the bin , and two MAXX pro came in the machines. To get a good range need a proper hop units. The stock barrels were replaced with 449 mm instead of 245 mm on CM.513 and 510 mm on place of 380 mm on CM.518. Changing the barrels requires new cylinders to achieve the golden ratio Volume of the cylinder to volume of the barrel which must be 1,8 to 1 or somewhere close . To have a big powerplant capacity I threw the NiMn stock batteries and got Li-po's 11.1 v with huge capacity : 9200 mAh on 518 and 3300 mAh on 513. Of course the mosfet installation is "must do" . I've got "gate warfet pro's" . And that's it . Everything else is cosmetics and gadgets ;-) Here are couple of pics of my projects . :

The 513 :

And 518 :