Low Profile AR gas blocks, info request.

[eltee]

What is the best way to convert a standard M4 upper with the post sight/gas block into a no front post upper? If someone wanted to use an Eotech and BUIS with a KAC front rail system, what's the ideal setup to substitute the standard gas block? The goal would be a totally flat upper, with the rail running across the receiver and continuing down the KAC forend with BUIS front and rear.

[fun2none]

Select a low profile gas block that will clear the rail handguards. Low profile gas block are available with two mounting methods.

1. set screws- requires dimples in the barrel sufface
2. clamp styple - does not need dimples; usually a bit taller than set screw type.

Another option is to fabricated a low-profile gas block by chopping and grinding down a standard front sight base.

[chuck762]

Does it have an 14.5 inch barrel with a fixed muzzle attachment or is it a 16 inch. If it is a 14.5 you will have to decide if you want to cut the sight assembly off or the muzzle attachment.
If you cut the front sight off then you can add a 2 piece gas block like here:

http://www.yankeehillmachine.com/store/gas_blocks.html

If you remove the muzzle gizmo you can use any of the low profile gas blocks.

[mltrading]

Reply #2 and #3 said about all.

It depends on how much work would you like to involve in.


The fastest and dirty way would be "chop the FSB".

[dfletcher]

I got the 2 piece YHM with the integral flip up front sight. Got it from Brownells, it costs about the same as a block with a separate bolt on sight. If you do have the 14.5" bbl with a welded on brake just an FYI - using a dremel cutter zips through that front sight base very quickly, certainly a bit quicker than I thought anyway. Nicked the barrel a bit, you need to slice through only one side of each section, easily bends away from the barrel.

[ar15barrels]

The choice of gas blocks depends on what you intend to do with the upper.
What length KAC rail are you thinking about?
Will you be putting an extended rail system on it that covers the gas block?