S410/S500/S510 .22
If your gun does not have a factory suppressor, then you'll need this adapter: https://donnyfl.com/products/air-arms-s510-1-2-x-20-double-male-adapter-a21?_pos=1&_sid=9805c3828&_ss=r
I would pair it up with a sumo .22/.25 1/2x20 #S61.
https://donnyfl.com/collections/airgun-suppressors/products/donnyfl-sumo?variant=33070855487531
If your gun came with a factory suppressor, I do not have an adapter to replace it.
S401/S500/S510 .177
If your gun does not have a factory suppressor, then you'll need this adapter: https://donnyfl.com/products/air-arms-s510-1-2-x-20-double-male-adapter-a21?_pos=1&_sid=9805c3828&_ss=r
I would pair it up with a Tanto .177/.22 1/2x20 #S40
https://donnyfl.com/products/donnyfl-tanto?_pos=1&_psq=s40&_ss=e&_v=1.0&variant=11782988759083
If your gun came with a factory suppressor, I do not have an adapter to replace it.