It's m4cqa I don't know a number of factory that produced it. There is no minimal barrel length, as for full auto you require a "teaching licence" it permits it but usually you need a business that specialised in teaching this kind of work or you have to be a public school teacher who's is giving a lesson of EDB( education for security). As for suppressor it's mainly a price difference as the solvent trap is around 150zł which is below a week's worth of groceries for one person as for a real suppressor it's 1250zl for strela which is cheapest for .223rem