So....
Having been given a 20+ year old TM m4a1 by someone, Im trying to get it up and running again.
Gearbox done, gears, grease n shimming, new piston n m100 spring. All happily doing their thing.
Only issue now is that it had a 2 piece hop unit. But alas, one bit was missing along with the barrel. 😕
So I've attacked it with a Dremel and made one fit (an old g&g I had kicking about), bought a barrel too
There's no space in front of it for the spring.
Upon test firing just now it doesn't feed at all well (1 in 3 shots) but when it does it's up to 0.8j.
I get the feeling that the g&g hop unit is crap, it's not a rotary one, so I've ordered a zci one to go in it.
Is the spring an absolute necessity?
I've heard tales of o rings being used to shim it back to the V2 gearbox.
The mag lines up ok but my concern is that if I shim the hop back to the gearbox, the mag won't line up.
Any thoughts?