VFC or G&P MK18 Mod 1 with upgrades

[airsoftmatthias]

I currently own a KWA KM4-RIS and decided, a couple weeks ago, to improve its performance. I purchased a set of 14:1 Riot SC gears, Lonex red piston, Lonex POM piston head, and a Lonex A2 motor. However, I realized that to get the performance I want (30+ RPS @ 400 FPS and 70m flat trajectory), it might be better to sell the KWA, use the funds to purchase a VFC or G&P MK18 Mod 1, and install the upgrades in the new gun. Additionally, I've had my KWA for 5-6 years now, and I'd like to find something new with nicer externals. At the moment, I would like to purchase the VFC version because of the functioning bolt catch. 

 

If possible, I would like to install a Lonex gearbox inside this gun. The VFC's functioning bolt catch would need to either be removed or the Lonex gearbox modified to accommodate these parts. Obviously, the G&P would be more friendly towards this notion since the gearbox or gun would require little to no modification for the gearbox swap. However, I really do want the functioning bolt catch, so would this be a feasible idea? If not, I am fine with using the stock VFC gearbox, since radiusing and adding sorbo should easily handle my build.

 

I have several KWA K120 midcaps from my KWA that I would like to use on the new gun. They feed excellently and are extremely durable. Will they work inside the VFC? I've researched this topic and found mixed reports. Some report that they do not work in VFCs while some say the opposite. Some say they work in G&Ps while some do not. Can anybody help me with this issue? If the VFC is unable to accommodate these magazines, I will probably choose the G&P, provided the G&P can work with them.

 

Externally, I love the dark earth RAS of the tan VFC MK18 Mod 1. The G&P does not include this on their tan model, which would require me to purchase an aftermarket Madbull dark earth rail system. This is one of the reasons why I want to go with VFC, so that I will not have to purchase additional furniture parts.

 

I plan on completely gutting the gearbox, regardless of whether or not I stay with the stock shell or switch it out for a Lonex. This will include the following items in addition to the upgrades listed at the beginning of this post:

 

Lonex hop-up unit

PDI 6.05 or 6.08mm inner barrel (455mm length)

R-Hop modification

Lonex 70 degree bucking

Lonex POM air nozzle

Lonex V2 cylinder head

ZCI stainless steel cylinder

ZCI V2 stainless steel bearing spring guide

Prometheus M120 spring

Lonex V2 anti-reversal Latch

Lonex tappet plate

Lonex selector plate

 

I do have a few tech questions, I've done some researching, but still would like some more info for my specific build.

1. Should I purchase SHS 8mm bushings for this build? Or will the stock 8mm bushings on the VFC or 8mm bearings on the G&P be sufficient?

2. I've heard the motor brushes on the Lonex A2 tend to break easily, despite it being a fairly good motor. Should I purchase Chaoli motor brushes to immediately replace them or just wait for them to fail before replacing them?

3. Should I replace the stock safety cover with a Lonex version or is that an unnecessary expenditure?

4. This AEG needs to shoot as close as possible to the 400 FPS limit since most of the fields I frequent have that safety limit. However, I do not want to drop below 390 FPS since I intend on using this gun as a semi-DMR/semi-high ROF gun. Will the Prometheus M120 get me there or will a Guarder SP110 or PDI 170% be better? This gun will be modified to have perfect compression (Permatex cylinder head to cylinder).

5. I would like to use a 455mm long inner barrel on this gun, which normally uses 275mm (VFC) or ~260mm (G&P) inner barrels. This requires a barrel extension of some sort. I would like to only use a quick detach KAC-style mock suppressor from VFC (168mm), G&P, or 5KU to cover the extended inner barrel. Is this possible, or will the inner barrel still stick out?

[blam360]

2. if youre going with riots, would definitely replace the stock lonex pinion. mine was chewed up in less than 2 mags. 

3. you mean the dust cover? dont bother, not worth paying extra for a new one. they're all similar enough that you won't notice any difference

 

if you want a functioning bolt catch, must use vfc gb (or another brand's gb that has functioning bolt catch mechanism). 

[airsoftmatthias]

By "safety cover" I mean safety latch. It's the part that is located right below the trigger switches inside a gearbox.

[airsoftmatthias]

Update!

 

I have 99% of the parts. I simply need to assemble the gearbox.

 

I am building two gearboxes for the VFC MK 18 MOD1. The first will use the stock VFC gearbox and all the stock VFC internals (CQC gearbox). The second will use an aftermarket VFC gearbox with the upgraded internals (field gearbox).

 

I polished the piston rails and cylinders of both gearboxes, radiused the front gearbox cylinder corners, and added sorbo to the cylinder head to correct AOE. I also shaved off part of the piston third tooth during the AOE correction. Both gearboxes have been shimmed, though the stock gearbox only partially shimmed since it has "self-shimming" spur and sector gears.

 

I finished the CQC gearbox and installed it. However, it looks like the motor might be overspinning or the sector gear was improperly set. In semi, the piston does not always reset all the way forwards. 

 

The battery used is an 11.1v 25C 1200mAh battery, which makes me think the motor is overspinning. I'm fairly certain I set the sector gear properly, but it could be the issue.

 

Here is a video of the CQC gearbox being shot in semi, a few bursts in auto, and then in semi again. You can see that the piston does not always reset to the front. At times, the piston will consistently reset forwards to a particular spot, but will not reset completely to the cylinder head.

 

 

Also, how does the gearbox shimming sound to you?