Norinco M4 - front handguard replacement - Size?

[Rascal]

What size handguard would i order to replace the cheap plastic one that Norinco supplies.

I have a 10.5" upper

I see carbine length and mid length but nothing in actual inches or says what will fit my upper.

I am thinking of something like this :

http://4.bp.########.com/-jZZLZieJSok/TdQczi7Kf3I/AAAAAAAAAQ8/0ihufODNPUI/s1600/Quad-Rail-Hand-Guard-for-Car-Size-Ar15-M4-M16.jpg

 

[otilram]

Carbine length.

 

[Danimal247]

I have a 10.5" norinco as well but my magpul moe carbine foreend does not fit - I've read about people filing them but not sure where arggh Hope that railed foreend fits better