What is the purpose of the forward assist on the AR15?

It allows you to ensure that a round is fully chambered. This is more important in the field when you might have trash in the chamber.

Quoted: It allows you to ensure that a round is fully chambered. This is more important in the field when you might have trash in the chamber.

Or in the case that your bolt doesn't have the energy to strip off the top round in the magazine due to a new/tight mag or a worn buffer spring.

or in the case that your bolt doesn't have the energy to strip off the top round in the magazine due to a new/tight mag or a worn buffer spring.

Yeap, I just used mine for the first time recently due to some brand new mags. The springs are not "broke in" and when I went to load a round the bolt needed to seat with the forward assist

The forward assist is part of the doctrine on clearing a jam (i.e. S.P.O.R.T.S.).  But...that's crap.  Basically the purpose is what the above have said.  Too, if you're loading and need to be quiet, you can ride the round in and then fully close the bolt with it.  It's not ideal, but it worked on the 2 times we had to do it during a LFTX where the RSO said we could only go hot once we were at the objective and not before.  It was alright and it worked.

Hope that helps.

SPC Richard A. White, Senior Medic
249th MP Detachment (EACF)
Camp Humphreys, ROK

tag

The forward assist is used to ensure the bolt is seated correctly so the weapon can function correctly

It's also used when doing small brass checks.  

Pull CH back a little to make sure you have brass in the chamber.  You'll only want to see about 1/2 to 1in. of the brass.  Then if the bolt doesnt return completely forward on it's own, push the forward assist.

My buddy in the USMC told me that's what they mostly use it for.  I think it's during some sort of inspection/drill/something like that.    

Thanks guys :)

Quoted: It's also used when doing small brass checks.   Pull CH back a little to make sure you have brass in the chamber.  You'll only want to see about 1/2 to 1in. of the brass.  Then if the bolt doesnt return completely forward on it's own, push the forward assist. My buddy in the USMC told me that's what they mostly use it for.  I think it's during some sort of inspection/drill/something like that.

That's known as a press check.  Anytime you need to verify that there is a round chambered (ie. just before going out the gate into bad guy country, kicking in doors, do the same thing with all firearms).  

FA was developed and added to the XM16E1 and since standardized on the M16A1, it was added to ensure the bolt was totally seated when the Army changed powders and weapons started to malfunction during VietNam.  There are also other uses as mentioned, silently ensuring the bolt is closed after chambering a round at night or near bad guys.  Since there is no bolt handle on the gun, the FA was added.  Most weapons have a operating rod or handle that can be tapped forward serving the same purpose (think M1 Garand, AK series).

CD

I developed a habit while in the Army of pressing the forward assist when I had been carrying an M16 for a while just before I knew I was going to fire, or if I was in a situation where I never knew when I was going to have to fire I just gave it a little nudge from time to time.  It just developed into a habit like checking my safety on occasion when I am carrying a weapon.

actually its what we are tought at the range, you insure you have a round in the chamber by doing a brass check then hit the forward assist to lock the bolt back into position.

Its a good idea to be certain that you have a round in the chamber befor you engage the target.

Quoted: actually its what we are tought at the range, you insure you have a round in the chamber by doing a brass check then hit the forward assist to lock the bolt back into position. Its a good idea to be certain that you have a round in the chamber befor you engage the target.

+1 typicaly if you pull the bolt back an inch or so it won't lock forward.

Seldom use forward assist,but glad my ARs have them.
Dirtier it gets or carbon build up or weak spring.

You'll be glad it there.

TG

I was taught to tap it twice with my palm after I pull the bolt back and chamber a round. Good habit or not needed?

The forward assist was developed at the insistence of the US Army.  In 1963 the US Army negotiated a contract to equip SFG's, and Airborne Divisions with the AR-15 while waiting for the fruits of the SPIW program.  The US Air Force also had a order of rifles in this same contract.  The Army just had to have the rifle with a way to positively close the bolt.  So Colt's came up with that plunger do dad, and deliveries began in the Spring of 1964.  The Air Force took deliveries of their rifles without the FA as the M16, and the US Army rifles with the FA were the XM16E1.

The 82nd showed up in the Domincan Republic in April of 1965 for operation Power Pack fully equipt with the new XM16E1.  This was the first public exposure to the XM16E1.

Of course the the SPIW failed, and the XM16E1 was adopted Standard A as the M16A1 in 1967.

Forward assist is useless and in some cases forcing a round that wont chamber can be disastrous,what if the obstruction is something other than crud now with forcing things the rifle is jammed up and useless.Any other battle rifle if a round does not chamber you pull back on the operating rod and chamber a fresh round.Ive never had fouling in a chromelined chamber cause a problem that the forward assist needed to handle if that were the case with AR types Im sure the carbon model#4s or early SP1s would have them.Didnt some early XM177s also not have them.I think with a chromelined chamber the forward assist is not needed.

Quoted: Forward assist is useless and in some cases forcing a round that wont chamber can be disastrous,what if the obstruction is something other than crud now with forcing things the rifle is jammed up and useless.Any other battle rifle if a round does not chamber you pull back on the operating rod and chamber a fresh round.Ive never had fouling in a chromelined chamber cause a problem that the forward assist needed to handle if that were the case with AR types Im sure the carbon model#4s or early SP1s would have them.Didnt some early XM177s also not have them.I think with a chromelined chamber the forward assist is not needed.

I used to have the same attitude and felt the FA was nothing more than a solution looking for a problem.  Now I find it's presence of comfort for press checks as mentioned, and ensuring the bolt is all the way forward when I rack a round in the dark.

Also, the FA is a high spot to collect scratches and character so perhaps one day I'll have a silver blemish to post a pic on one of the "Show me your beat up AR" threads.

ETA: I meant to use this icon , not .

Sly

Quoted: I was taught to tap it twice with my palm after I pull the bolt back and chamber a round. Good habit or not needed?

I think it is a good habit, I do the same thing... (thanks to the DIs...)
Wait until you get your hands on a old SP1 or a SP1 retro clone and you go to tap the FA and it ain't there! doh!
the first time I did that I was like whoa... No FA...

Hi guys,
    Listen up to what Tweak said about not hitting the FA hard. Recently saw a Colt 11.5 M4 upper jam after firing. Could not get the bolt & carrier fully open. Wound up taking off the stock and buffer tube to get the carrier out in order to disassemble the weapon for inspection. The culprit was the FA pawl pin (spring pin) had broken from repeated hard striking of the FA. The owner was a LEO from an entry team who said he had been trained to briskly strike the FA after charging the weapon. Once the pin had broken, the pawl was simply floating around in the FA area and would engage the FA cuts on the carrier every time we tried to retract the bolt assembly. The pawl pin is a small hollow roll pin, so don't pound on the FA trying to get the bolt closed unless you REALLY have to get that bolt closed. And if you have abused the FA in the past, have the pawl pin checked out before it bites you in the ass.
    FA is also nice to close the bolt with very little noise when you are trying to be stealthy.
                                                                 FWIW,
                                                                 Carey