View Full Version : JG MK36K Internals Review (25,000+ rounds)

iTz Nicholas72
02-04-2010, 09:51 PM
Here is a little review on the internals, mostly the gearbox. I've shot over 25,000 rounds and decided I would tear it down and check for wear. I found some things that were good and some that were disappointing. Overall I'm very surprised how well everything is holding up so far.

On to the review...

I'll start by taking the out the gearbox and grip assembly.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001656.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001656.jpg)

The only major problem I've had so far is my stock Selector Plate breaking. So I replaced it with King Arms Reinforced one as shown.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001657a.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001657a.jpg)

Another small quirk is the paint is starting to get rubbed off but you can't really notice.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001658.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001658.jpg)

Here is the gearbox once it is removed from the grip.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001700.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001700.jpg)

The trigger posts fit pretty loose in the gearbox shell but it doesn't affect the function at all it just has a bit of play.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001701.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001701.jpg)

Now for the biggest disappointment of all PLASTIC BUSHINGS!!! I don't understand how I got them. The most recent models are supposed to come with metal bushings and I got my gun in late December.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001702.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001702.jpg)

The gears came with WAY to much grease but they were shimmed pretty good from the factory. This is surprising because my JG was shimmed and my friends CA DPMS M4 wasn't.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001707.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001707.jpg)

After taking the gears out and checking them for wear I was glad to see all of the teeth were in mint condition. The gears have "JG" stamped on the Spur Gear and Bevel Gear.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001713.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001713.jpg)

Next up is the Tappet Plate, there are no signs of wear and no extra burs of plastic.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001715.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001715.jpg)

The spring guide is a solid piece of plastic but gets the job done and the tabs are holding up great. I'm going to replace this soon with a Metal Ball Bearing Spring Guide for more strength and a small FPS boost.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001715a.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001715a.jpg)

The Cylinder Head was much better than I was expecting. It has a dual o-ring design and from what I can tell a thin Sorbo pad. It is made from plastic but provides absolutely great compression. This is another part that was better than my friend's CA DPMS M4 which only has a single o-ring and no Sorbo pad.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001717.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001717.jpg)
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001717a.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001717a.jpg)

Here is another part I plan on and would recommend you upgrade. The air nozzle does its job but doesn't have on o-ring so compression isn't that great.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001718.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001718.jpg)

The cylinder is average. It's made from brass and has the correct porting for the M4 length barrel in the MK36K. There are no defects or sharp edges and gives great compression.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001718a.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001718a.jpg)

The Piston head is pretty good the only con is that it doesn't have a ball bearing. It is ported and in combination with the cylinder it gives near perfect compression. The o-ring works great but I'm going to try a #14 o-ring and see if it gives me even better compression.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001719.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001719.jpg)

The spring has the weird end and uses the metal spacer to attach to the piston head. I'm guessing its around a M110 because I get around 380 with a .2G BB. When compared to the spring in my friends CA DPMS M4 the wire isnt as thick but his spring gives him around 400 with a .25G BB.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001720.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001720.jpg)

Now for another pleasant surprise, the JG Piston. After shooting over 25,000 rounds there is hardly any wear on the Piston teeth. The teeth with the most wear is the second tooth but that is common. I see no reason to upgrade the piston unless you somehow damage the stock one.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001721.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001721.jpg)
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001722.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001722.jpg)

The wiring/switch assembly is also holding up great. The contacts are still very shiny and no oxidation seams to be occurring. I'm still using the stock 8.4V battery but I have used my friends 9.6V for a few games with no problems. I'm going to try some 2 cell LiPos from my friend and if I like them I'll starting using some 7.4V LiPos.
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001722a.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001722a.jpg)
http://i942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/th_0204001723-1.jpg (http://s942.photobucket.com/albums/ad270/iTz_Nicholas72/JG%20MK36K/?action=view&current=0204001723-1.jpg)

Next is the barrel/hop-up

02-05-2010, 08:00 AM
25,000 BBs + plastic bushings = win for you :)

iTz Nicholas72
02-05-2010, 05:04 PM
Yea, my next airsoft purchase is going to be some Steel Bushings. I'm not sure if I want bushings or bearings yet...

09-08-2010, 12:36 PM
I have same gearbox with plastic bushings and want to replce them. What size are they, 6MM or 7MM. PS-your PM box is full...