Did you get your 500 jeffry cartridges.Has Blaser ever produced a rifle in 505 Gibbs, in particular the R8?
.590 is as big as I have seen for the R8 (338LM) 505 is .640.R8 is produced by Blaser in 500 Jeffery but not 505 Gibbs. Not sure any of the bolt heads are big enough to handle the Gibbs even if a custom barrel was made. I believe the largest is for 338 lapua which is based off the 416 Rigby case.