ACM Official site?
 

Hey there, I'm trying to locate an online version of the manual for the ACM M500, so I can figure out how to take the stock off.... for the life of me I can't find it and I feel like an ass having to ask but... I'm lost. Any help would be great, thanks guys.

Ok, so I research a little more to find that ACM stands for Any Chinese Make, which explains why I can't find a website... anyone know how to take the stock off an M500 clone? Right now there is an M4 stock on if that makes a differance.

The clone is pretty much identical to the Marushin. Exploded parts diagrams can be found here: http://tech.airsoftcanada.com/Marushin

The stock attaches to the receiver with a large [usually hex] screw which goes into the back of the receiver, underneath the safety switch. If you have an M4 stock tube, depending on the model, the screw is either inside (like a TM stock tube attaches) or there'll be a hex screw on the base (if it's a "realistic style" tube, which screws on with a castle nut -- which means you have to remove the buffer tube first).

Its not like the TM tube, its got a solid cap on it at the end that isn't removable. It looks like it threads in as there are two holes that might be for a screw or something on the sides behind the pistol grip and you can still see the thread from the tube through.

http://img23.imageshack.us/img23/499...0268ae3.th.jpg
http://img3.imageshack.us/img3/5761/dsc00269zc3.th.jpg

If that helps at all *shrugs*

That looks like a real steel, mil-style stock tube and stock. A few AEG uses them as well. You'll have a hard time removing the castle nut without a proper AR wrench.

Now I am assuming the castle nut is the round piece that is at the base of the thread between the pistol grip. I can't seem to budge that fuckin' thing for the life of me, would there be anything locking it in place other than just being threaded on to tightly?

Holy hell, I took it out to my father's garage to borrow some tools, it took a vice and some vice grip plyers of substantial size and as much body wieght as I could apply to loosen it... holy hell.

Yes, the castle nut is the round piece.

I don't think there's anything else locking it in place, but I've never worked with a M500. I do know from experience that getting it off without the proper tool was next to impossible.