do all manufacturer rails fit on any handguard system?

[Barms 98]

New to ARs so bear with me. 2 part question: 1) I guess Magpul dominates this sector.. but do all manufacturers rails fit on any other manufacturers handguards? I guess what i'm asking about is "do the holes line up to screw it down?"

 

2) when you are putting a short rail system on the handguard do you have the option of positioning the short rail anywhere along the handguard or are there just one or two places to position it so the screws line up? If i'm confusing you here is the reason i'm asking is because if i intend to put a 5 inch magpul AFG foregrip on i was thinking what MINIMUM size rail can i put on the handguard. You would think 5 inch rail right? well true but if i'm not able to adjust where on the handguard i feel comfortable with the foregrip (i.e. sliding it forward or back then i would need to buy a rail that covers the entire handguard just so that it would give me the ability to slide the grip where i want.

 

In other words what i'm tyring to avoid is 8 inches of rail for a 5 inch accessory.. get it? But my idea will only work if i can "float" that rail to wherever i want it.

[raz-0 1,259]

1) All rail segments do not fit all handguards, not even most rail segments fit most handguards. It's a matter of the radius, the hole spacing, and the contour.

 

2) The AFG can be made to work with a 2" rail segment. It's borderline IMO, but it can work. A 3" will get you the cross bar locked in and a decent chunk of the angled flange interlocked with the rail segment, but if you want to move it you will likely have to move the whole rail. A 4" lets you move it back and forth a bit. a 5" would let you move it around quite a bit.

[Krdshrk 3,878]

Honestly I use a full 11 slot magpul rail for my AFG. It takes up the whole thing