Looks like a Solid frame Gasser copy.
Check out Gasser Antique Revolvers on the Net there very simlar.
Id bet it is a Gasser just Renickled which in the polishing stage Removed all the markings ECT
Look under the wood grips the makers name should be stamped in the frame somewhere.
There good solid guns and it would be 11.3 MM caliber very simlar to a Big long 44 or 45 Caliber should be a 5 shot cylinder.
The 45 mighta been added later. Belgian guns most anyway were metric calibers like 11 MM or 8 MM ect.