See also:
https://forum.vintageairgunsgallery.com/walther-air-pistols/walther-lp-53/#post-9411
https://forum.vintageairgunsgallery.com/rock-island-auctions/bayard-john-hull-co2-conversion-air-rifle-etc/
https://forum.vintageairgunsgallery.com/rock-island-auctions/bugelspanner-air-rifle-converted-to-co2/
https://forum.vintageairgunsgallery.com/rock-island-auctions/paff-type-air-rifle-bsa-john-walker-co2-conversion/
https://forum.vintageairgunsgallery.com/vintage-bsa-airguns/rare-and-custom-vintage-bsa-lincoln-jeffries-airguns/#post-1361
https://forum.vintageairgunsgallery.com/vintage-bsa-airguns/rare-and-custom-vintage-bsa-lincoln-jeffries-airguns/#post-8249
