Stupid Forward Assist is stuck

[moopey]

My first time installing a forward assist.....seemed pretty straightforward.....

put the spring on, insert into upper, push in the forward assist a bit then install pin. Check. however, every time I install the roll pin all the way, the forward assist gets stuck. I see on the forward assist that one edge is flat, I am installing it with this side facing inward. It seems as though the roll pin is too thick, because if I place a smaller punch in it's place the FA works as it should. But a smaller pin will not be secured in the holes in the upper. Should I take material off of the FA? I can see markings on the FA where the roll pin has scored it from putting the roll pin in a couple times. WTF am I doing wrong or did I just get a shitty FA assembly that's out of spec?

 

[1903Collector]

I have never had one get stuck before, sounds like you are installing it correctly. Did you try lubing excessivley? sure you got the right pin? I guess if all else fails, it's a cheap part, just replace with another one.

 

[moopey]

i got it! looks like the FA was rotating a bit as I was hammering in the pin. this was causing the FA to bind. using a pair of pliers I was able to rotate the FA free. It now works correctly. Only bad part is the marks the pliers left on the FA even though I wrapped it. I was able to sand the marks smooth, just need some touch up paint or I may just leave it.

 

[1903Collector]

I use a slave pin to hold it in place while I drive the pin home, if you ever install one again try that, I do the same thing with the bolt release...saves a lot of cursing in portuguese lol. Glad you got it, good feeling isn't it?

 

[HowardZ]

I had the same problem.
Removed and reinstalled FA several times.
Purchased another FA made by Aero Precision, same problems.

Using pin punch instead of roll pin, FA works perfectly.

Using #41 drill bit instead of roll pin, FA binds again.

Solution was to use dremel to remove some metal from shaft of FA.

Cause was faulty manufactured upper receiver.
I installed barrel first,
Then needed to dremel upper for ejection port cover to close.
Then the FA problem.

Having installed and headspace checked the barrel,
I didn't want to return the upper and start over.
Fortunately a little careful dremel use solved things.

 

[DispositionMatrix]

Using the punch or a slave pin is a must for that install in AP uppers.

It is good that there _is_ a forward assist in the AR platform; it is bad that there has to be a forward assist.