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Forward assist sizes?
12/11/2011 9:17:17 PM
Hi everyone, I'm in the process for building an M16A2 clone and an M4 clone. So how many different sizes or types of round forward assists are there? I swear I saw some sources that show a big forward assist and a small one for each build, respectively. Any pictures if that's the case? Thank you.
12/12/2011 9:02:04 AM
Very early M16A2 uppers (usually commercial) had "full round" big button forward assists. However, these big button forward assists couldn't clear the reinforcements on the receiver boss of an A2 lower forging, and the side closest to the receiver was relieved for clearance.
It didn't take long for the current, "small button" forward assist to be adopted however, and it's been in use since.
Note that a USGI small button forward assist assembly will be two pieces, visible by a roll pin in the plunger "shaft" where it goes in to the forward assist recess on the receiver. Many commercial contractors use one piece forward assists that are missing the roll pin.
~Augee
It didn't take long for the current, "small button" forward assist to be adopted however, and it's been in use since.
Note that a USGI small button forward assist assembly will be two pieces, visible by a roll pin in the plunger "shaft" where it goes in to the forward assist recess on the receiver. Many commercial contractors use one piece forward assists that are missing the roll pin.
~Augee
12/12/2011 9:55:02 AM
There is a type of large round button that will work on an A2 receiver, and was installed at the factory. My Colt M16A2 that I was issued at in the mid 90s had one.
S/N: 62134xx
I took one off a SP2 upper, and it works fine on a Colt sporter upper and A2 lower
S/N: 62134xx
I took one off a SP2 upper, and it works fine on a Colt sporter upper and A2 lower
12/12/2011 12:57:33 PM
Interesting.
I've never actually tried mating one to another, is the full round big button noticeable different from both the "typical" big button and the small button? Or maybe the large button in fact does fit in some cases, and the relief is for tolerance stacking, or something like that?
Is there maybe a "medium button" we haven't clearly identified yet?
~Augee
I've never actually tried mating one to another, is the full round big button noticeable different from both the "typical" big button and the small button? Or maybe the large button in fact does fit in some cases, and the relief is for tolerance stacking, or something like that?
Is there maybe a "medium button" we haven't clearly identified yet?
~Augee
12/12/2011 8:17:21 PM
So If I were to build a clone of the A2 rifle made by FN in the late 80s, would the small fa be correct?
12/12/2011 9:23:54 PM
Originally Posted By gun_nut10:
So If I were to build a clone of the A2 rifle made by FN in the late 80s, would the small fa be correct?
So If I were to build a clone of the A2 rifle made by FN in the late 80s, would the small fa be correct?
Yes.
Here is the large Colt forward assist. This one was stolen from a SPII upper. I had the same type on my issued Colt M16A2 back in the day.
12/13/2011 5:10:31 PM
Originally Posted By Stottman:
Yes.
http://img.photobucket.com/albums/v143/Stottman/4b9836a7.jpg
Here is the large Colt forward assist. This one was stolen from a SPII upper. I had the same type on my issued Colt M16A2 back in the day.
Originally Posted By gun_nut10:
So If I were to build a clone of the A2 rifle made by FN in the late 80s, would the small fa be correct?
So If I were to build a clone of the A2 rifle made by FN in the late 80s, would the small fa be correct?
Yes.
http://img.photobucket.com/albums/v143/Stottman/4b9836a7.jpg
Here is the large Colt forward assist. This one was stolen from a SPII upper. I had the same type on my issued Colt M16A2 back in the day.
Thanks for the pic!
I guess our wires got crossed somewhere - that's the relieved big button forward assist I was talking about.
~Augee
12/13/2011 7:33:12 PM
Ah. To me, the large forward assist is the quintessential M-16A2 forward assist.
The lower is a 1994-5 era Colt Gov't carbine with small pivot pin and mag fence.
The lower is a 1994-5 era Colt Gov't carbine with small pivot pin and mag fence.
12/25/2011 2:14:10 AM
Note that a USGI small button forward assist assembly will be two pieces, visible by a roll pin in the plunger "shaft" where it goes in to the forward assist recess on the receiver. Many commercial contractors use one piece forward assists that are missing the roll pin.
The commercial forward assists without the rollpin are fine for most use, but if ran hard, they will come apart.
Since they are just pressed in, there is nothing to actually hold them together but pressure...
I have not seen one fail but I know someone who had their commercial FA come apart while the gun was being fired.
From my firsthand observation:
DPMS forward assists do not come with the rollpin.
Armalite forward assists do not come with the rollpin.
Spikes forward assists do not come with the rollpin.
Colt forward assists do come with the rollpin.
FN forward assists do come with the rollpin.
I've got an LMT MRP sbr inbound... will update when I find out about their forward assist.
12/26/2011 8:59:16 PM
My Sporter II has the clipped big round button. I've seen earlier Sporter IIs with the tear drop style forward assist button
