My uncle in law passed away a few years ago and i got several firearms. One of which is an old 6.5x55 sweed. It's threaded at the top but that's for a special adpatper used to shoot WOOD bullets, not to use a supressor. But that does beg to ask; i'm far from a machinist but... short of buying tools to check the original thread pitch.. i'm carious if anyone knows the original info.
dont get me wrong, i would double check by hand (via gunsmith) but the ones i call are "backlogged".
I am a Gunboards member, many knowledgeable folks there.
http://forums.gunboards.com/showthread.php?197857-Threaded-Swedish-Mauser-barrels
"The thread size is M14 x 1.0m/m pitch . "
These are great rifles- you can still pick up " flash hiders" at many surplus dealers. I believe the thread is 14x1mm