RMC having the 56 -56 and the 56-50 center fire case for original but conversions and replicas
remember the 56-56, 56-52 and 56-50 are all interchangable and the old bigger diamter were all abandoned for the 56-50. don't ask me how they were shooting in older rimfire guns with bigger barrel diameter. this was about outside lubrication changed into inside lubrication, maybe the 56-50 had a hollow bases.
fact is the 56-50 romano must be something else. my first thought was "lathe turned 32 ga brass case"
a .533 Minie fits very well into the cylindrical 32 ga magtech brass case so the lathe turned case with a thicker wall may hold a .520 diameter bullet. the rim is looking different on .52 Romano so it don't fit into 32 ga shotguns. I have made 12,7x60R 500BPE ( a short german version of the 500 BPE) by using 32 ga magtech brass, you can use it for different stuff.
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