Three things
Not enough head space and toggle is forcing shell to deep into receiver.
Shells have excessive crimp at bullet from factory
Highly unlikely that a original barrel would be out of tolerence, however due your comment about your friends new luger do you mean new to him or new meaning that firearm has been redone with after market
barrel or parts and not manufactured correctly.
Take a look at the post above yours on the 1910 luger, this is the correct amount of head spacing. Notice that the extractor fits nicely into the machined end of the receiver, hard to give good advice about a firearm without seeing the gun but the picture of the old 1910 says it all.
Not enough head space and toggle is forcing shell to deep into receiver.
Shells have excessive crimp at bullet from factory
Highly unlikely that a original barrel would be out of tolerence, however due your comment about your friends new luger do you mean new to him or new meaning that firearm has been redone with after market
barrel or parts and not manufactured correctly.
Take a look at the post above yours on the 1910 luger, this is the correct amount of head spacing. Notice that the extractor fits nicely into the machined end of the receiver, hard to give good advice about a firearm without seeing the gun but the picture of the old 1910 says it all.