For my 20" AR15 with 4x ACOG, I've been thinking about getting a KAC M5 RAS for better heat dissipation. I have a few questions for M5 RAS users -

1.How solid is it? (please compare to FF RAS or SIR)

2.Since M5 RAS doesn't FF, would the weight of M5 RAS affect accuracy a lot? (I have no competition parts on my rifle)

I know I would be better off with FF RAS but I like the fact that I can install and uninstall the RAS without gunsmith's help.

I personally have seen a KAC M4 RAS, but I was worried about M5 RAS since it is much longer than M4 RAS and it would be heavier and flex more.

Tne M5 RAS locks in at the front handguard cap and the barrel nut.  The rail unit is pretty stiff, so it does not flex.

Leaning hard on a bipod [i]might[/i] shift your POI, but I don't worry about it.

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=5891[/img]