A2 Front Sight Base with Integrated Gas Block (FSB)

Product Description

This brings back memories don't it? Ah the good old days when AR's were simple and not quite the lego that they are today. This is your standard A1 or A2 height Front Sight Block/Base (FSB). She's pretty fresh and will need you or your smith to drill and ream the taper holes for installation. 

The difference between F-marked and non-F-marked is a very small difference in height, the 'deck' on the F-marked FSB is 0.04" taller, intended for Flat-top upper receivers. Non-F-marked Front Sight Blocks (sometimes called the Standard or A2 version) are intended for the classic A2 carry handle receivers. This translates to a difference of only 6 clicks assuming you're using the common 4-notch front sight post so it might not matter if you have enough adjustment room on your Front Sight Post.

We offer an F-marked, 0.75" version that has the sling swivel pre-installed (swivel not shown in photos).

• Sometimes called the FSB (Front Sight Block/Base)
• Available for 0.625 or 0.75" diameter gas block'd barrels
• Weight: 128g

You get:

• (1) Front sight block of your choice 

You NEED to get:

• (1) Front sight post
• (1) Front sight post spring
• (1) Front sight post detent
• (2) Taper pins

Compatible with:

• All AR-15/M16 barrels with a 0.750" or 0.625" gas tube section of the barrel (especially those with taper pin holes)
• The 'Non-F-marked' are for uppers with built-in carry handles. The F-marked FSB are for A3/A4 uppers where you're installing some flip-up or similar peep sights.

Installation Difficulty: 

Tools required: Front site tool, taper reamer, drill soft hammer, block of wood or something capable of uniformly knocking the FSB into place.

You need to watch that you don't cover the gas port and thus have the block rotated correctly. Just take your time.