How do I??

[knarf3]

Well I have now got myself a full metal ICS M4 RIS but would like to change it a little.

I want to keep the RIS it has but instead of having the front sight and then an extension and then the flash hider (which the silencer I have connects to) I want the silencer to butt up against the RIS so it looks a little like an SD version...

Any Ideas???

I did remove the part that follows after the RIS but it would seem the thing I think is the outer barrel is about 1 inch to short to screw the flash hider onto...