Ask Art Ill be sure to do when he calls me next time and who are you so I may say you said hello? Ina give you the skinny on A sqaure the 500 came out 20 years after the 510 wells express and guess what its the same round oh my the 460 asquare short basically tge 460 von horn the list goes on so im guessing you thinkj art was the first to wildcat the weatherby case the 577 trex is basically an oersized 475 A&M