OK, kids, listen to daddy for a minute!
Forward assist is NOT intended to jam a cartridge into a dirty chamber. Nor were there chambering problems with early M16 rifles -- assuming they were cleaned.
The Army specified forward assist because every rifle they'd issued for the past 100 years had a means to positively close the bolt.
The last two were semiautomatic rifles, the M1 and M14, and the loading drill on both these includes a final step of hitting the "forward assist" -- the back of the operating rod -- to be certain the rifle was in battery. Standard procedure.
The Army also considered a reciprocating handle a liability so didn't want a handle on the M16 bolt either. The only solution was forward assist. Last step in loading the M16 is to bump the forward assist to ensure the bolt is closed. See
TM9-1005-319-10 (Rifle M16A2) <--- that's a link.
With the M16 system it's possible for the bolt to come out of battery with an impact to the buttstock such as can happen during a fall or jump from a vehicle or aircraft. Easy to thumb the forward assist to be sure the rifle is ready to fire.
Use of forward assist to cram a cartridge into the chamber is a last ditch, probably one time event. Yeah you can do it, but it's not the reason forward assist is there.
Anyway, as others have pointed out the forward assist on the Colt .22LR is fake.
-- Chuck