I have a 30-338 rifle built on a springfield action. I bought this gun about 12 years ago and have not shot it. At the time I was told you had to reload the shells for it, and it came with dies.My question is are all 30-338 the same. I have seen norma, lapua, magnum, winchester magnum and possibly others. My die box has (written in ink) 30-338 imp I have looked online and cannot find any info on imp.My speer manual(1993) list only 30-338 norma Can someone help as to whether this is the load or other suggestions. Thanks in advance.