Replaces the original outer barrel mount/holder with a much more solid shape. Prevents lateral movement of the barrel. Increases the accuracy of the airsoft gun several times.
FreeCAD file included.
Tested on SRC G36E2 gen. III:
Needed airsoft parts / parts in my SRC airsoftgun
- Airsoftpro CNC hop-up chamber, red color (tested) or CNC hop-up chamber from another manufacturer with screw connection to the gearbox (not tested!).
- JJ hop-up chamber JA-3602 as a donor of small blue plastic parts, because they have a more accurate shape than some original plastics from airsoftpro chambers, or better.
- ASG ultimate cylinder head for gearbox v3.
- Retroarms 25.6 mm nozzle (Maybe 25.8 is also suitable).
- Hop Up bucking 4UANTUM AEG orange with nub
- 363- 415 mm inner barrel, Davinci GUREN 1 steel with plating, or better barrel. Viz notices and table bellow. 509 mm for standard full aeg cylinder is obsolete.
- Padding the clearance between inner barrel against the outer barrel, for example with plastic strip of suitable thickness.
- Standard gearbox SRC v3, or better.
- Other common upgrades
- Another piece of long outer barrel SRC, outer diameter approx. 16 mm
- Moved the battery to the rear, into the stock. Adapter to M4 stock and M4 CRANE stock, rewired and diy MOSFET board or better
Notices for upgrades
- Hop Up bucking 4UANTUM AEG
- Bucking lips are too long for me (bucking from Maple Leaf as well), so I sanded bucking lips about 0,3mm. Sanding paper 600 → 800 → 1200, all with silicone oil as lube. The ability to attach the rubber band to a piece of old inner barrel and attach the whole thing to a standard drill is an advantage, drill speed about 500 rpm max)
- Do not use washers under the hop rubber band, as this will shift the barrel lock cutout, and then the barrel will press on the rubber band and deform the collar, which will impair accuracy.
- The hop chamber blue plastic pressure element for hop nub may be too high,
- it may be necessary to reduce its height. 3 mm hand file, precise movements and grind the groove for the hop up nub. On the blue part from JJ airsoft, it was necessary to remove from 3.45 mm to 3.15 from the top of the arc to completely turn off the hop. Without adjustment, the 0.30g BB were still too hopped.
- Barell lenght
- For maximum performance and precision read this article https://www.reddit.com/r/airsoft/comments/s41swi/cylinderbarrel_volume_and_bb_weight_ratio_guide/ and Best g36 right now?, topic about barell lenght
- The original 509 mm barrel is therefore only suitable for very light BBs, according to the article on Reddit. See the table, for a full AEG cylinder:
Cylinder Ratios
BB weight-----Barrel Length-- Barrel Volume----- Ratio
0.2g-----------435mm--------12423mm3-------2.17:1
0.23g---------430mm--------12280mm3-------2.19:1
0.25g---------425mm--------12137mm3--------2.22:1
0.28g---------420mm--------11994mm3-------2.24:1
0.30g---------415mm---------11851mm3-------2.27: 1
0.32g---------400mm--------11423mm3-------2.36:1
0.36g---------380mm--------10852mm3-------2.48:1
0.40g---------355mm--------10138mm3-------2.65:1
0.43g---------345mm--------9852mm3--------2.73:1
0.45g---------335mm--------9567mm3--------2.81:1 - With a full classic AEG cylinder, M130 spring and 0.32g BBs I took a specna arms 407 x 6.02 mm barrel. My gun has 2,4 J on that setup, with hop up on)
Tools
- Home workshop
- PLA+ or PETG filament or thicker, 3-4 perimeters, 40 - 60% Cubic infill
- My printer settings were: PLA+ PM, nozzle 0.6, layer height 0.28, 3 perimeters, infill 30% + brick layer BETA 0.2.1. https://github.com/GeekDetour/BrickLayers (warning - heavy stringing), ORCA slicer, cut into 2 parts due to the maximum height limit of my printer (155 mm in Z axis)
- 16 mm drill bit for cleaning the main hole
- Something for deburring
- Rounding
- Original 3x M3 screws
- 1x M3 or M3.5 screw for the front hole
- MAMUT TOTAL glue for fixing the outer cylinder in the printed part, for sure
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Instructions - not finished yet!
- Move the battery back into the stock. Rewire the wiring if you haven't already.
- Fix gearbox play in gun body?
- Measure the original cylinder mount and check the dimensions, especially the bolt spacing
- Print TOOL 1 and test the dimensional accuracy of your printer. After cleaning it from burrs and stretching it with a 16 mm drill, it should fit snugly on the outer barrel. It is better to print a smaller hole and fine-tune it with several stretches with a drill.
- Shorten one part of the outer barrel to a length of 212 mm (for a 510 mm inner barrel), remove burrs and sawdust!
- Print TOOL 2 and mount the outer barrel in it, place it in the airsoft gun and visually test whether the gearbox nozzle comes out approximately in the middle of the outer barrel hole, in the x and y axes. Insert the outer barrel into the part until it stops, into the narrowing, and mark the position.
- Visually check that the nozzle is centered in the outer barrel again
- We will use the original metal mounting frame, but it needs to be modified. Cut off the nut that the barrel was screwed into and file the height of the protrusions so that they do not interfere with the 16 mm hole for the outer barrel - test the exact height with the printed part.
- Print TOOL 3, insert the outer barrel into it, the distance from the edge measured in point 2, I got 2 mm. Tool 3 serves as a guide for the file, in the aluminum barrel you need to drill, grind 2 grooves so that the M3 screws pass through them. Use the file from the smaller diameter to the larger. The grooves should be horizontal, just wide and deep enough for the M3 screw. Check with a screw.
- Print the main part for a final dimension test. 2 perimeters, 10% infill will be enough ... Remove the burrs and insert the shortened outer barrel, align the filed grooves in the barrel with the M3 holes on the sides, try to assemble the weapon, check that the nozzle still comes out in the middle of the outer barrel hole.
- Visually check that the nozzle is centered in the outer barrel.
- If everything is fine, print the part with the final recommended settings. Remove the burrs, check the dimensions, holes, try to assemble everything.
- Visually check that the nozzle is centered in the outer barrel.
- My nozzle was correct in elevation, but too far to the right when viewed from the gun towards the barrel. In addition, the front of the mechabox was too loose, moving sideways, especially to the right. This resulted in an occasional deflection of the path of the fired bullet to the right, about one out of every 3 to 5 bullets. So I needed to move the mechabox slightly to the left and at the same time fix it in that position, I am working on a solution right now.
The fit of the mechabox in the body of the replica is not as good in the G36 as in the M4 replicas, this is a manifestation of this imperfection
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The original solution of the manufacturer was:
The metal is a center plate of alloy or aluminum, rails through which 2 bolts and nuts pass to the outer barrel. Unfortunately, this is a poorly designed concept of barrel mounting on the G36, most cheap manufacturers.
- The outer barrel starts far from the jumping chamber, unlike the M4
- The outer barrel nut basically holds it like a cherry on a stick
- the shape of the iron part has no lateral strength, the outer barrel and thus the inner barrel then flies from side to side
-> inherent shooting inaccuracy of the G36 with this barrel attachment compared to the airsoft concept of the M4
Other manufacturers (Ares, Specna Arms, S&T, NOVRITSCH, ...) actually have improved the barrel mount system, for example with a metal cap nut mount over the outer barrel.