Congratulations on your LRS2
I love mine and have built up my barrel collection for it as well.
any R93 barrel will work just fine on the LRS2 platform. You can also use any R93 bolt head. The only things that are not the same as the R93 are the bolt assembly (LRS2 is a little wider) and the magazines.
The R93 Semi weight 300 WM barrel described in this post would be a great way to add 300 WM to your LRS2 platform (Extra bonus for the threaded barrel).
The alternative is to look for a the original Fluted/threaded match barrels. Harder to find and more money.