I have been working on this project for a while now and it was designed to be a long range hunting round just like the 338 rum and 338 edge. The purpose was to get as close to 338 Rum performance and still work in a std length long action. I make a ton of barrels for Savage rifles and have been producing quite a few 338 edges. My customers ask me how to make a Savage a repeater with an edge and I have to tell them it would take a lot of more, lots of money and still limit the oal of the round. So I went to work designing the 338 Sin, what it is based off is the 300 rum/338 Rum case. The case is shorten to std 338 win mag length and then the case is blown out and changed to a 40 degree shoulder. I am with in 6grs of the 338 rum for capacity. I am awaiting my reamers to show up but my HS gauge came on friday so I thought I would share a little. This is designed to work with Savage/Howa/Vanguard/ect. all you need is a std magnum rifle and you can swap the barrel out and have a long range target/hunting rifle with out spending tons of money on custom mag box or stocks. Let me know what you think. I will post pics of the test rifle when the reamers show up. Thanks