ABS trap adapter question

[pasadena_commut]

I recently installed one of these:

https://www.homedepot.com/p/Charlot...-Joint-Trap-Adapter-ABS00103P0800HD/313834563
the nut side is taking a 1 1/2" polypropylene pipe made by Oatey. There was no washer supplied and it wasn't clear to me that the supplied nut would actually seal with that type of pipe. So I used instead one of these

https://www.homedepot.com/p/Oatey-1...th-Rubber-Reducing-Washers-HDC2698C/316622089
since they were used at all the other slip joints on this drain install. The pointy end of the 1 1/2" washer is facing into the trap adapter. In testing it did not leak, even when a whole sink of water was dumped through the drain. Several days later and it is still dry.

Was that an acceptable solution, or should some other sort of washer and the nut supplied with the trap adapter have been used instead?

 

[Geofd]

The nut actually IS washer

 

[pasadena_commut]

The nut actually IS washer

How so? It slid up and down the polypropylene pipe with a pretty tight fit but almost no resistance. The inside didn't feel rubbery, it felt just like the rest of the plastic. Does it deform to seal against the pipe and adapter when tightened with a wrench?

Also, if the nut does deform somehow to seal, if it is ever removed and put back on, will it still seal?

 

[Geofd]

The nut tapers inside so it fits into the trap adapter they come in 1 1/2"×1 1/2"
1 1/2"×1 1/4"
1 1/4"× 1 1/4"
The slip nut/washer are all one peice and don't come apart