I doubt there is that much interestI wonder if FRTs have made it to the less gun restricted countries of Europe
1. European gun ownership in general is not based around "let's just go shoot guns for fun". What is the practical use of an FRT, other than turning money into smoke and noise? If you have to acquire guns via permit anyway, there is less interest in doing dodgy shit that might cost you your guns
2. European gun legislation is not the same as in the US. FRTs might not be deemed to make a firearm a machine-gun in the US, but they certainly would in many places in Europe. For an example, the Finnish law doesn't specify, what is a fully automatic firearm. The law just talks about fully automatic firearms. That leaves it entirely up to the interpretation of the police and the justice system. FRTs would no doubt be classified as full-auto parts. There is no "multiple bullet go out with a single pull of a trigger" type of classification, as there is in the US.
3. In a lot of those countries, accessing full-auto firearms might be easier than in the US to begin with, so why?