12" or greater.
You could get away with a 10" hand guard, but I find most hand guards come in 9", 12" or 13", and 15" lengths.
Not knowing anything about handguards. Who makes the absolute best/strongest handguards? "want to avoid them ever moving and being held on by tons of little screws".
Install on a budget.
Why did that guy cut off the delta ring?? I have had several troy rails and never once has the thought of cutting it off come to mind. It would have taken him less time to remove it properly and put the barrel nut back on. What an idiot.
Budget for the handguard is $500.00.
I'm sure I want a handguard that uses a proprietary barrel nut.
I'm gonna run a front sight, light and sling mount on the handguard so I'm thinking key mold or m-lok would better than going full blown quad rail "weight wise".
Why in the world would u try to shave off the front valve? You can get a small gas valve for $15 or so and replace the front site post. Your rail will slide right over the valve.
Choose your team first. Keymod or Mlok.
If you decide on Keymod then I would get a BCM KMR.
If you decide on Mlok then I would go Geissele Mk8.
If weight is the issue just do away with the handguard and get yourself an oven mit.
Get a 15" rail, having the ability to rest the hg anywhere on a prop, rock, truck bed what ever without touching the barrel is nice, plus the most important is it just looks bad ass! :-)