ICS m4 issues
 

Hello

So ive got my hands on a used ICS M4 that has a few issues, some of which I have fixed.

So here's the story: i got this gun used, it had feeding issues, and i replaced the worn down tappet plate. HOWEVER: the person who had the gun last had glued the stock air nozzle to the tappet plate. I got a G&P air nozzle and it worked fine and went half a game before it started jamming every time i shot. Basicly, Im pretty sure its all just a compatibility issue between the hopup and the air nozzle.

Just wondering if i could get some advice on what i should do.

do you have a set of calipers? measure the length of the old nozzle and compare it to the new one.. also visually compare where the tappet hooks into the nozzle vs the new one, the length of the nozzle from the channel can vary from 1 combo to the next.

no, i do not have calipers.

check the spring attached to the tappet plate. if attached at a bad angle or height then the spring will start rubbing againt the gearbox preventing the tappet plate from cycling smoothly.
at least i have had that problem on my ics m4. actually it is easy to check is thats the case- just take the upper gearbox in your hand and cycle the tappet plate by pressing the nozzle and then releasing. repeat the motion several times.

I have a customer who is quite good at fixing his own guns. He has owned ICS for years and he says that ICS nozzle is proprietary and you need an ICS nozzle to replace it.

Immediately take all the shit in that gun that isn't ICS and change it back.

You can do this on your terms or on the guns terms after a few more games like the one you had.

I spent dozens and dozens of hours working on an ICS M4. Same issue. Chasing my ass. Final solution was take the bastard back to the way it came. Nozzle, bucking, etc.


Mach1 has all the parts you need if there is not a local ICS contact.

It's like that because of ICS proprietary hop up, not really a bad thing because the ICS hop up chamber is pretty good.

Never change an air nozzle unless it's got a serious air leak.
There's no difference between a $4 OEM nozzle with an O-ring and a $16 prometheus air nozzle.

...

If you can replace with the stock ICS parts, do it.
However, any M16A2 tappet plate and nozzle will fit (not M4 nozzle, the M16 was a bit longer back in 2002).

also, what do you mean by jam? A nozzle/tappet problem won't cause a system jam (as in weird sound or no cycling). It will just not feed.

If you have BBs jamming in the barrel/hop-up, look there. It can be a torn/worn rubber, too high setting on the hop or a scratch in the barrel.

if the nozzle is not long enough to reach forward and seal, it will sound like a fart or just a dry fire, if it fired at all, chances are the nozzle is short and you got lucky that it shot, probably super low fps.

If the nozzle is too long you just end up dry firing because BBs can't get into the hopup.

Exactly

Often the Second one is common. Nozzle too long, and not clearing the way for the bb to make it up the hop up.

Often mis diagnosed as "this mag feeds better than this one"

NO

Its the spring in the mag forcing the bb past the friction point. Also a variance in the size of the bb gets you to chase this.


Modify has an "o ring" they supply with the hop ups. That little o ring can mean the difference between feeding or not in a standard M4.

Irrelevant on this gun, but mentioning it.

im using Modify Air Seal Nozzel for M16A2/M4 Series in my ics m4 - works flawlessly. however i did have troubles with a guarder nozzle.

that's why I said to measure the nozzles :P Sometimes you can buy a "m4 nozzle" or whatever gun and it will not be the same length the slot for the tappet is a fraction off or the nozzle is half a mm short or long etc... different manufacturers are different spec. Always compare your old part to the new part before installing.

ASM actually has a database on mm measurements of a wide variety of nozzles to the thousandths of a mm to help find the right one.

I got 2 nozzles I keep here. Both are cracked, and I painted a red mark on them. One is too long and the other is too short for ICS...

Show how many ICS rifles I worked on, or had. Faster that way than getting the digital caliper.

wow, thanks for all the advice.

Its not the tappet plate. The gun cycles just fine tappet plate wise.

By jams i mean that the gun dry fires, then sounds like its farting, just like lurkingknight explained, but then the gun starts grinding gears.

well i guess i should get a new nozzle.

just curious, at first we at the field found that it was initialy the BBs i was using. I was using airsoft centrals, it was jamming, and then i tried BB bastards, and they worked....for a few hours.

Just curious, do you guys think that swaping out the ICS hopup with a G&P hopup would solve the issues? i find that the ics hopup is a bit cheap looking and odd to adjust.

thanks for all the help guys