Hw35 Leather or synthetic piston seal ?

[Shed tuner]

I used to think that's how they came out of the factory --- but they didn't.

I've had leather sealed guns with 2.8mm transfer ports, and one dealer in the early 1980s advertised synthetic sealed guns with 4mm transfer ports.

All the best Mick

Mine is like that too - nice small port, original leather, and shoots very nicely.