Air Venturi Which air rifles use 1/8 BSPP connect for compressor

I can confirm the BSPP is a EU thing, Asians using M10x1, USA is building air equipment mostly with NPT. For a non inclined all these may look the same thread, but actually not interchangeable.

FX airguns use BSPP

Things are NOT standardized when it comes to HP fittings so there's no one answer for your question. One can "standardize" things for themselves with bspp to nft adapters & so on but it's been one of the pitfalls when combining U.S., EURO & CHINESE equipment. We do figure our way around things enough to make it work but we all wish it were more standardized. Technically imho, NO airguns use 1/8 bspp to "connect to compressor"(directly). They use a foster or probe to connect. That foster or probe can be bspp, nft & so on.