You cannot install a bipod on this handguard.
Yes, it fits.
It is 4.8 oz total.
Yes, the Sniper AR-15 .223 / 5.56 Free Floating Forend Holding Systems would be compatible with a 6.5 Grendel AR as the upper receiver is compatible with standard AR15 barrel nuts and handguards.
Yes, the Sniper AR-15 .223 / 5.56 Free Floating Forend Holding Systems can be used with a 9mm PCC as long as the upper receiver is compatible with standard AR15 barrel nuts and handguards.
No. Imported.
Yes, it is.
Yes, this should work with .450 Bushmaster.
Any length handguard will work for any length of gas system. The deciding factor is the barrel length and the type of handguard and gas block you are using. If you currently have a 2-piece drop in handguard with a delta ring system, you will need to convert to a free float system. This includes replacing the gas block and installing a low profile gas block.
This is a replacement handguard and does not thread onto the barrel in any way. This would replace the existing handguard.