These kinds of pins are universally used, economical shear-type fastener models, which possess self-locking capabilities. When they are created, they are manufactured to an oversize dimension. This is done so that once the pin has been placed inside a hole radial forces are exerted, holding the spring in position.
Caleb Components offers both DIN 1481(ISO 8752) Heavy Duty type & Light Weight DIN 7346 (ISO 13337) Type.
Links are below…
https://springfasteners.co.uk/product-category/pins/spring-tension-pins-din1481/
https://springfasteners.co.uk/product-category/pins/imperial-spring-tension-pins-carbon-steel/