[jonascord]

If it's a bolt action, like every other Swedish Mauser, it doesn't need any attachment to fire blanks. For that matter, most American Legion M-1s don't bother, since it's a matter of one second to thumb back the bolt for a funeral salute

As to why the threads? Perhaps a suppressor? Some countries require them for target shooting, just to reduce the noise. Not every Government is as stupid and slackwitted as ours.

[Kirkwood]

The threaded barrel was for a wooden bullet shredder.

[Rappini]

We have a pressure plug on the end of our M-1’s for Funeral Salutes.