Scratch-built mechbox questions - V3 for G36

[Endymion]

Those of you who have seen my SL-9 in person recently may understand where I'm coming from. I had an AG36 attached to it and a 335mm silencer, making the total length 51.5". I had fun with it that way, but now it's time to make it more practical. I've taken the stock TM G36C parts out and resurrected the G36, which leaves me on the hunt for parts to rebuild my SL-9. Rather than lay down $500 for a stock G36 I've decided to requisition the mandatory stock G36 parts and then build an upgraded mechbox from scratch.

Based on everything I've read and sifted through in searches, I'm leaning toward the following parts.

Systema torque up helical gear set (for slightly quieter operation and less stress on the motor)
Systema Magnum motor (for 1337ness really... I know there are equally good alternatives for this application that cost less)
Airsoft Surgeon Stage 2 spring
Angel Silent Piston Head Set (V3) (to lessen gearbox wear and for slightly quieter operation)
Prometheus 6.03 590mm barrel or 650mm barrel
Systema Bearing Spring Guide
Systema Anti-Reversal Latch
Guarder Tappet Plate
Guarder Nozzle
TM Selector Switch
- springs, wires, etc.

From what I've come across in research would I be correct to assume that a Type-0 cylinder would be adequate for anything up to a 590mm barrel? This would allow me to use a regular piston and the Angel piston head set. However, once I hit 650mm will I need the bore up kit to avoid barrel suck and to maintain fps consistency? I'm under the impression that with a bore up kit I will be stuck with its specfiic cylinder head, piston and piston head and that a silent head set would no longer be feasible. The Stage 2 spring should be of sufficient strength to properly operate the bore up kit should it be necessary.

As far as gearbox shells go, is there any advantage or disadvantage to using a zinc alloy box (Guarder, TM, etc) versus an aluminum box (King Arms)? What are your experiences with the various aftermarket shells? Will 7mm bearings really net any reduced wear over 6mm bearings?

This AEG will have its full auto locked out - basically it would remain functional only to ensure that should any jam occur, it could be remedied without ripping the mechbox out of the receiver. I figure that if I have this sniper rifle platform, I might as well put the longest barrel functionally possible within its length and build a properly supported gearbox around it. I will be using a 9.6v 1300mAh 1/2sub-c pack - the voltage and battery size are predominantly for quick trigger response. The amperage I can live with - I wouldn't be hammering on the trigger with this AEG anyway.

I welcome any suggestions, advice or hole-poking you can offer. This is definitely a learning experience for me but I love tinkering and tweaking the most minute details even if they sometimes result in diminishing returns. No flames please - if I've said anything really stupid, please just point it out and I will know better for the next time. I'm still new to airsoft. This forum is a wealth of information and intelligent well-thought-out opinions and I really value the depth of breadth of its members' experiences.

Take it easy...

Alan.

[ILLusion]

The Angel Silent Head Set in a gun with an inner barrel that long may experience lower than expected velocity. The dampening system on the piston head takes up some of the volume in the cylinder that is required to get maximum capacity through the 590mm inner barrel.

And you're correct, once you go up to 650mm, you'll need the bore up kit as well as an M120 or stronger spring.

The head set that comes with a bore up kit is a Systema-type silent head set. As anyone can tell you, it's not really "silent."

The "zinc alloy" gearboxes you refer to are zinc-aluminum... which should be the same thing as the King Arms one. It's just crafty marketing terms, but generally, if it's a die-casted part, then it's zinc-alloy. It's easier to pour in to the moulds. As far as I know, pure aluminum version 3 gearboxes do not exist.

6mm ball bearings will NOT withstand anything much beyond an M100 spring. If you're lucky, it can handle heavy springs, but it will wear down much faster than if you increased the size to 7mm. I personally do not recommend taking that risk. If you MUST go with ball bearings, increase to 7mm bearings which can safely handle up to PDI 190% equivalent springs. Or you could just stick with a 6mm gearbox and use standard bushings which could handle a 550fps spring if you wanted to go that nuts...

[ringsted]

if i where you i would definatly not put in a barrel longer than 550 mm with a bore up kit. you may and i say may be able to run the 590 mm barrel with only a slight loss in FPS, but once you hit a 650 mm barrel your FPS will suffer a lot, to the point where a M140 spring will perform as a M120 spring.

if i where building your rifle i would snatch one of those 509 mm tanio koba twist barrels, according to different tests i know where performed by experinece people they are very nice also i a M170 powerde gun as well.

i would go with the systema bore kit if i was you, reliable and not too much noise. 7mm bearings are much more durable than 6mm, it does after all usuallty cost a new gear set if they blow so why risk it. the best 7mm bearings can be found here http://www.kanzen-bearings.com. they are super nice, i use them in a M170 setup and they have never failed me. and i run it Full auto frequently, albiet only at 700 RPM

[ILLusion]

I've never been able to get a Twist barrel to get work well at any velocity higher than 360fps. They always spiral out of control and in an unpredictable direction at the end of their initial flight path. The higher the velocity, the wilder it's flight trajectory.

[swatt13]

same problem paintballers had when they first started rifleing barrels a couple years back, which is why they abandoned it. i had a friend tell me some airsofters were starting to rifle their barrels, i instantly recalled the whole paintball incident. you cant get it to work with a spherical round (no pun intended).