Rifle Question

zanshin

5 Oct 05, 22:00

from what i remember, the forward assist is designed to push the bolt forward when the bolt cannot closed fully due to dirt/mud etc.

the original AR-15 used in the Vietnam war had no forward assist, and the rifes jammed often. The forward assit was then added to retify that. Take a careful look around, and you will notice that there are still anumber of AR-15s in SAF, they do not have forward assist.

Btw, the original Ar-15 used in vietnam had 3-prong desgned muzzle(i think you can find in some old dummy rifles), it often got entangled with nets/branches/twigs etc.

Cpt.ZR

12 Oct 05, 18:01

the 3 prong muzzle is the flash suppressor la... haha.. anyway.. the so called M16S1 without the forward assist is actually the AR 15.. also... M16S1 and the american M16 also have a difference other than the Forward assist is that, AR 15 is fully auto and America M16 A2 is burst one... Like what we have in the pasir LAbar IMT range.

ANyway.. I'm not in SAF yet... I'm still in NCC hahah!

Shotgun

12 Oct 05, 18:09

Okay, this is what i understand

AR-15 = NO forward assist. Semi and full auto only.
M-16A1 or M-16S1 = Forward Assist present, Semi and full auto only.
M-16A2 = Heavier barrel (not sure), Rear sight can zero vertically, (A1 / S1 can only zero left n right.) Built in deflector. Semi and 3rd Burst only.

M-16A3 = Same as A2, except upper reciever's carrying handle can be removed to reveal a picatinny rail. Semi or Full auto.

M-16A4 = Same as A3, semi or burst.

Raptor937

13 Oct 05, 09:37

Originally posted by Shotgun:
Okay, this is what i understand

AR-15 = NO forward assist. Semi and full auto only.
M-16A1 or M-16S1 = Forward Assist present, Semi and full auto only.
M-16A2 = Heavier barrel (not sure), Rear sight can zero vertically, (A1 / S1 can only zero left n right.) Built in deflector. Semi and 3rd Burst only.

M-16A3 = Same as A2, except upper reciever's carrying handle can be removed to reveal a picatinny rail. Semi or Full auto.

M-16A4 = Same as A3, semi or burst.

That's pretty much about it.

A1 Profile Barrels: Diameter is .600" for the entire length (as low as .570 forward of the front sight (there can be some taper from the chamber to the front sight).

A2 Profile: Diameter tapers from .675" to .605" under handguards, .715" from front sight to muzzle.

Also the rifling twist rate of the A2 is different from the A1. The A1 uses the 1:12" twist rate while the A2 onwards uses the 1:7" twist. This is because of the M855 round which uses the SS109 bullet, which is slightly longer than the one in the M193, and would not stabilise out of a 1:12" barrel as it would only fly straight for about 90 yards, then veer off in any random direction.