Recently I picked up an ICS L85A2 and when searching for reviews about the internals I got a lot of mixed information. I could find loads of information and reviews about the external bits and features but little about the mechbox internals. I read everything from it having a proprietary spur gear like TM M14's, extra long cylinder, custom piston head, uses a custom motor type, etc. etc. but not everyone said the same things. So I am writting a review of the internals to make everything clear.
First up is the mechbox itself. I have already removed the variable spring guide and spring but information on this is everywhere as its a main feature so I wont go over it again.
As you can see it is a completely custom mechbox type so don't break it, currently there is no way to get replacements from ICS. On that note the mechbox is a brick and you would have a hard time breaking it anyway. As you can see there is reinforcement around the bushings to prevent cracking between the holes and the cylinder isn't as visible as in some mechbox types because of how much metal there is around it. The gun comes with an ICS Turbo 3000 motor which has a higher speed, higher torque, and produces less noise than a Turbo 2000.
Photo is out of focus but its still obvious that the gun uses a non-standard motor spring. The hole the pinion gear on the motor goes through is much larger than normal so the smaller standard spring (on the left) would just pass through and you would have no spring. The custom spring fit on the SystemA turbo motor (short type) I installed no problem. The motor cage comes off in a similar fashion to a ver.3 mechbox.
The cut off lever is made from solid steel and is external to the mechbox. It comes off easily enough but that little spring is a bitch to get back on compared to many other guns (TM M14 for example, since it also has an external cut off lever.)
Other than the one little screw that goes above the spring guide all the screws are the same size and threading. There are no worries about which screw goes where. On the note of screws if you tighten the little screw as much as you would a normal mechbox screw the spring guide wont go in, so tighten it after setting the spring guide to lock it even further in place.
The anti-reversal is a proprietary part, at least its different from the ver.2, 3, and 7 anti-reversals I have kicking around. The spring is also longer on the bit that sticks out than normal anti-reversal springs but a normal anti-reversal spring does fit and work.
7mm metal bushings so no worries there and they seem to be different from the standard ICS bushings. Normally ICS has slightly larger axles on their gears but these seem totally standard as my HurricanE highspeed gears fit without any wobble and spin free. As you can see there is lots of metal around the gears so no worries about anything cracking at Canadian fps limits.
The gun comes with a white nylon piston (thankfully not an ICS aluminum mechbox wrecker) and black I'm guessing polycarb piston head. The piston head is longer than standard and I have no idea why as it uses a standard cylinder and ver.2 cylinder head.
Quick shot of the front of the mechbox with components still inside. The nozzle appears to be a standard ver.2 and I don't have a side by side but it is a match to spare TM M4 nozzles I have.
The tappet plate is indeed custom but upon closer inspection it is the exact same dimensions as an armalite tappet over all. The bottom red one is a King Arms enhanced tappet. One thing to notice is the lug that holds the spring is further back on the L85 one but at the same time the tappet plate spring is longer. I didn't test it for function by firing it but the mechbox assembled and the nozzle moved properly with the King Arms one in it.
Standard ICS looking gears. They do fit in SystemA metal bushings without problem so unlike previous ICS gears they don't have enlarged axles.
Standard ver.2 M4/16 cylinder head. Used a caliper to make sure and its the same as a TM to 0.15mm at most.
As said earlier it has a standard cylinder, no extra long non-sense. Left is a stock TM cylinder from an M4, right is the L85 cylinder. It is a non-ported straight cylinder as it has a 509mm inner barrel, same as an M16 but this gun is as short as a CQBR.
Here I have installed a MASK piston head on a Guarder polycarb piston and installed a Sorbo pad on the cylinder head. I was originally worried about the piston head not working because the stock one is extra thick, but 2000rnds later and the piston has next to no wear on it so I guess standard ver.2/3 parts work fine.
One thing was the white o-ring that came with the MASK piston head provided zero airseal. I put the stock black o-ring that came with the L85 on the MASK piston head and it got airseal. The airseal is actually amazing considering it has a non-airseal nozzle and single o-ring cylinder head. The only gun that did as well (not any better) on a compression test was my ICS M4A1 upper mechbox with all stainless performance components with airseal nozzle.
I don't have any pictures of it but the inner barrel is actually aluminum, not brass. Much like JBU and Madbull barrels (but not coated like Madbull.) The hopup is a non-standard design and is made from plastic as far as I can tell (though a VERY hard plastic, almost made me think it was metal until I scratched it.) I'm not sure on the inner diameter of the barrel but both JBU and Madbull aluminum barrels are 6.03's so this may be as well.
Overall I am actually quite impressed with how far ICS has come. I have worked on some early generation ICS M4's and they have been no where near as nice a build as this one. There was just enough lube and the shimming was spot on. I will get some more fps results later but so far all I have is the following.
Modify M100 spring
minimum strength setting: 260fps with BB Bastard .20's
maximum strength setting: 330fps with BB Bastard .20's
I will be putting in a Modify M110 later and see what it does. I don't want to go above an M110 because I have highspeed gears and a turbo motor in there. Its currently shooting 29rps but I hope to bring that to 35rps with a custom 10.8V high drain battery I ordered that I am waiting for.
The only bits I have to say about the externals is that an ACOG will mount on the 19mm rail it comes with but is far too low for me, I need to practically break my cheek bone to look through it. I ordered a STAR standard weaver rail adapter for the top and it fits perfectly and rises the ACOG to the perfect height. The trigger pull is quite a bit harder than normal AEG's so quick semi-auto shots is far more tiring on your finger and hand. The gun
DOES NOT have a threaded barrel. When you remove the flash hider you have a bare straight outer barrel that the allen screw in the flash hider digs into.
The trigger is actually an amazing design. It reminds me more of a Colt 1911 hammer/trigger setup than an AEG trigger. When you pull the trigger it pulls a sear back that releases, a for lack of a better term, a hammer that is spring loaded and snaps the contacts together far faster than a human finger can in a normal AEG. This greatly cuts down on the arcing and wear on the contacts as well gives a far more realistic trigger pull, much more realistic feeling than even a PTW (take note I have only ever fired hunting rifles and shotguns, I have never fired a real L85.) There was worry about the electrical works not having much metal in them and reducing maximum current flow but I took a measure of the volume of the copper bars in the lower receiver over 1cm and it is equal to 12awg wire in volume, far thicker than anything in a normal AEG. There is the issue of the contacts between lower and upper receivers and it could be a point of resistance. I am looking into rewiring the spring loaded contacts with a deans plug somewhere but haven't had much time to work on it.
That about sums up the internals review for the ICS L85A2. Any questions just post em up and I will try to answer to the best of my ability.