i know some fiberglass FF tubes weigh under 7 and 8 oz, but how much does the BM alumiminum and other manufacturers aluminum tubes weigh?

I don't know the BM wieght but the hogue aluminum tube (carbine) is advertised at 9 oz. Seems like they would be pretty close in weight.

The Hiperform carbon fiber handguard are claimed to be 7.5 oz for standard and 5.2 oz for the ultralight.

I e-mailed fulton armory about the full length tube and this was the answer:

[b]It will be around 14 oz, Steve.  Don't forget that in addition to
replacing your handguards, you'll also be replacing the handguard cap,
barrel nut, delta ring & weld spring.  Thus, the weight savings are
substantial compared to a standard A2 handguard setup.

Best regards,

Walt Kuleck
Author, "The AR-15 Complete Owner's Guide"[/b]