Madbull Daniel Defense Lite Rail 12.0 on an ICS M4
 

Hello,

I recently bought an ICS M4, with colt trademarks. And I bought a Madbull Daniel Defense Lite Rail 12 inches to fit on it.
I heard that this ICS version had metric thread so I jumped on it.

http://shop.ehobbyasia.com/madbull-d...ail-black.html
This is the rail.

I dismounted the handguard, front sight etc and when I come to install the Madbull barrel nut, it wasn't fitting at all. I was able to turn once and an half but no more. I didn't want to break anything so I stopped.
Looking at both barrel nuts (Madbull and ICS ones), the thread is quite similar to me, CCW for sure, but I am not used to see differences between metrics and imperials.
Is there a way to be sure that the ICS thread is imperial?
I saw the madbull barrel nut for G&P, maybe it could solve my problem?
( http://www.airsoftparts.ca/store2/in...oducts_id=1904 )
I have no standard M4 receiver with me, so I can't be sure that the problem is from my M4 or the Madbull barrel nut.
Someone had some similar issue?
I am open to all suggestions!
I can provide pictures if needed.

Thanks in advance!

And forgive my bad english ^___^

Try removing a bit of the paint on the threads. Mine was hard to install because of that.

The thread on ICS is the imperial thread so you need a new barrel nut which his imperial like the one for G&P or PTW. hope it help.

KosMos told me that the thread could be metric but conical. With a rethreader, it could be fixed.
Boyso, you had the issue with a Madbull rail? Or other replica?
@Masako : this is my plan B if the thread is not metric. I have to be sure of before, I have to test something else on it.

Same rail, but in 7" flavor.

But on a WE M4. With the right nut

Thanks Kaiu! So I can say that mine is imperial threaded?
I will try to brush the thread to get rid of paint before, then retry.
I'll see if it's better.

It is a new ICS bought from Styrak. This version is maybe last year's , not much.
I will try to find a "standard" M4 before doing anything brutal :D

Is a plastic receiver a trustable test? A friend can lend me a plastic G&G M4.

ICS uses Imperial threads on the barrel nut. So you'll need to find one that's compatible with G&P, WE and Systema. Most airsoft barrel nut are Metric. If you have a loose tolerance or worn threading on a ICS, you might just get away with a Metric nut. Try removing as much paint/finish as possible and thread on the barrel nut. Add some cutting oil and screw on and off until you can get it on all the way. This could take awhile to do.

what about heating up the madbull part for dilation before screwing it in ?

@HKGhost : there is no metric thread on ICS? It could explain why I am stuck.
@Jimsky : It is an idea, could work if I want to force it inside. Thanks!

Nope, ICS doesn't do Metric. It's like G&P and WE. You'll need the Imperial barrel nut from Madbull, or do some modding and filing to get the Metric barrel nut to fit. I'd just buy the proper one just to save time and have the rail mounted properly.

Thx HKGhost!

Like I mentioned. You might get a low tolerance threading which both threads will work. ICS isn't known for high quality, tight tolerance machining. Also, if you have a plastic upper, that will give a little and can accept Metric threads.

Well, you're lucky to not have to go through what the OP is going through. It's just another thing to buy which kinda sucks.