Post by Mark
Gavin,
I have seen revolver cartridges with and without O-rings its just an individual manufacturers choice as to the cartridges internal design. Revolvers, as they do not utilise the recoil for operation (with the exception of the rare WebleyFosbury and the Mataba semiautomatic revolvers) so, the cartridges don't need the gas retention that the semi/fullauto models need. O-rings might be needed to retain the piston/detonator in the cartridge to prevent the caps from falling out.
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Wanted to buy: MGC Sten MK3....trades?(still)
MGC MP40 Marushin MP40 Nakata MP40 TRC MP40
Modelgun manufacturers, past and present:CMC,CAW,Hudson,HWS,LS,MGC(R.I.P. 1960's~2007) Marushin,Marui,Kokusai,Shoei,Tanaka and Western Arms