[Juha]

Hello Kari.

Well, the MS had at least time to time problems with their central gun still in 1944. When vänrikki Eriksson was lost on 25.5.44 all four participating MSs suffered central gun malfuctions. Eriksson (MS- 317)(after returning from Soviet prison camp) and luutnantti Uola (MS-644) reported that their weapons didn't work, kapteeni Turkki (MS-650) reported that the cannon of his a/c (so his a/c seems to have had 20mm Hispano) stopped working after a couple of burst and after a while suffered barrel explosion and vänrikki Kyllönen (MS-637) succeeded get only 2 burst from his middle gun (keskipyssy) before it fell silent and he had only his wing mgs (siipikiväärit) to use. I don't know which if any of the a/c had UB as the central gun, but probably some had. I had copies of some combat reports in which pilots clearly stated that their Berezin stopped firing but usually pilots only mentioned that their central gun malfunctioned without specificing the type. I haven't went through the 1941 -43 combat reports so i cannot say if the situation was worse earlier but it wasn't too good in spring 44. I'm more an operations man and had not checked which MSs had Hispano and which UB as the central gun in 1944.

I put the identifications of the participating MSs in my message, maybe You have the info on which guntype they had as the central gun?
Juha