You cannot exactly convert 030 archives to 006, it does not make much sense. Unless you want to reduce a 30 piece archive to a 6 piece one. But you cannot just convert the individual parts, they are just pieces from a split multi-volume archives. You will need to gather all the pieces before you can extract the contents, which you can of course repack again.
Convert Split file or Compressed file from a multi-volume archive (part 30) to Compressed file from a multi-volume archive (part 6).
We have found 2 software records in our database eligible for .030 to .006 file format conversion.
Microsoft Windows software - convert 030 to 006 on Windows
Popular open source file archiver with a high compression ratio
Convert from 030 file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned 030 to 006. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
One of the oldest and most popular shareware file archiver and data compression utility