5.56 to 6.8 spc?

[22lr]

is there anything beside re-barreling? Have anybody done it? Once done, what does it entail in terms of registration?

 

[dangertree]

You'll have to have the firearm reverified and registered as 6.8SPC.
I believe you technically have 30 days to do this.

 

[(Ronin)]

Barrel,bolt,magazines are different..but you can load a few (4-5)rounds in a normal AR mag before you start to have issues.
Not worth the money IMO
Just get something in .30 cal

 

[RePete]

The mags just need treeking but the boltface has to be opened up for the casehead.

The 6.8SPC is based on the .30 Remington.

 

[dinsdale]

http://demigodllc.com/~zak/firearms/6.8SPC/faq.php