does the 257 roberts fit in the short action (308) BLR?
were could i find a barrel for a pre81 BLR?

The 257 will fit in either the short or long action.Its better in the long action because of seating the bullets further out.It will work just finein a short one.By the way they use to make 257 roberts in a blr but few were made.I want a 25-06 and a 338 in one.