Words: Rich Norman

The A2 style front iron sight is sometimes called the front sight post – or FSP. It’s a fixed A-frame sight, which helps define the M4. It is iconic.

In recent years it has all too often been discarded in favour of flip-up back-up iron sights (BUIS) or no iron sights at all.


However, there are a number of modern rails which, quite literally, return the A2 front iron to the forefront. One of these is the Daniel Defense RIS II FSP.

Crucially, this style of rail has a slot for the A2 iron but extends onwards, towards the muzzle device. This delivers the best of both worlds: retaining the A-frame sight but providing a longer platform for the indexing of lights, optical aiming devices and support hand ergonomic accessories.

It is not a new rail. The pic below shows some of the prototype RIS II variants – courtesy of Stickman – which helped Daniel Defense win the DoD contract to become the chosen supplier of the Block II rail.

The oversized bolts on the sides were meant to make it easier to remove the rail’s 6 O’clock panel – for access, or to integrate a grenade launcher.


So, while the FSP is not a new rail per se, it’s deployment is new-ish.

Until a few years ago, there wasn’t a huge body of photographic evidence for the FSP’s use in the wild. It is only since early 2016 that the Block II package has been fully rolled out to all SOCOM elements – starting with Tier 1 and trickling down.

Now that all RIS II variants are fully integrated into the supply chain, the FSP version is more prevalent; particularly since it is very popular with Army SF – the single largest SOCOM element and one of the last to gain access to the full Block II package.


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