Want to switch one of the piston system AR15s over to another rail system that does not use the standard barrel nut.  Do really need to use the drive rod spring bushing if the spring itself comes in full contact with the face of the barrel nut?

TIA

The drive rod bushing serves two purposes:

1) it provides a seat for the spring against the standard barrel nut, and
2) it provides a stop for the piston's rearward motion.

Not using the bushing would allow the spring to go solid during operation, severely reducing spring life, and possible reduced reliability.

I would talk to AA about this as little specifics have been provided.

I think he's referring to the bushing that presses into the upper receiver.

I have also changed my guns around and have installed my AA piston kits on different uppers. One bushing I was able to knock out with a narrow screwdriver. A second time I could not get it out without completely destroying either the bushing or the receiver. The are about $5.00 a pop from AA with a bunch of shipping.

Shoot AA an email and ask if there is any assistance they can provide with a new bushing. They may just drop one in the mail for you for free.... hint hint...
They have a history of poor customer service but they have fixed all that and are great now!

Negative, he is talking about the spring bushing not the receiver bushing.

OP, it also has dimension that provides preload.

Found a Fortis Rev rail for $100, I went back with the std barrel nut.  Why dick with it?