AR-15 Upper-Receiver Build: Installing the Forward-Assist Assembly

When compared to the amount of work that went into building the 1911, this new project appears much less complicated. Bryce M. Towsley wrote a very informative two-part article in the June and July, 2010 issues of Shooting Illustrated, which fellow Associate Editor, Jay Grazio and I used as a guide for our builds.

The Aero Precision upper I received from Brownells was stripped, meaning it didn’t contain a forward-assist plunger and a dust cover. Those items are contained in a parts kit, which I purchased separately. While some uppers offer them already installed, those that don’t are typically less expensive. Fortunately, putting the parts in yourself isn’t that difficult. The necessary parts and tools are listed below:

Parts

Forward-assist assembly
Forward-assist spring
Forward-assist retainer pin

Tools

3/32-inch roll-pin punch
Brass or plastic hammer

Be sure to keep the foreward-assist plunger compressed while you drive the roll pin in place.

Brownells offers several forward-assist assemblies that come ready to install. All you have to do is place the return spring over the pawl and inside the plunger cap, and you are ready to add it to the upper. However, before inserting the forward-assist assembly into its housing on the receiver, start the roll pin that holds it in place.

Once the roll pin is in place, the assembly is locked in and ready for use.

Hold the forward-assist plunger against spring tension while driving the roll pin home. Continue tapping the roll pin with a 3/32-inch roll-pin punch until it’s just past flush to complete installation.

Function Check

Push the plunger to make sure the pawl moves forward and returns under spring tension.

The next entry will cover installing the dust cover.