Ultra Mag Magazine box and follower, staggered feed for 110 long action

I have a Savage 110 or 111 in 300 Win Mag I was going to build a 458 Lott on. I was just informed by SSS that they can no longer get the ultramag boxes and followers from Savage for my project. Does anyone have a suggestion as to where I could get a ultramag staggered feed magazine box and follower for my project, or how to modify the 300 WIN mag box and follower to what I need. The magazine box was the last component I was waiting for. I have all the other parts for my project including savage rifle, richards stock, Mcgowen barrel and so forth. Thanks

Did you try Numrich or Jack First?

I looked on Numrich's site. They did not list any ultramag boxes. I am going to call them though. Ihave not heard of Jack First before