About half my rifles are magnums and the other half is not.After scoping the barrels out,it looks like you start seeing erosion with magnum cartridges in few as a hundred rounds when your burning about 70-80grs or so of powder.My non-magnum rifles burning 45-60grs of powder with several hundred rounds through them don't show any erosion.So it seems to be like a cutting torch,burning large amounts of powder is going to get the barrel hotter and starts to slowly burn.Add that with multiple firings without cooling is going to speed up the barrel burn.Magnums are great,I really like them.Work up a load for them and shoot them a lot less and they will last a long time.Get a 308 or a 30-06 and shoot them more while your saving the barrels on your magnums.

Last edited by baldhunter; 06/22/20.
~Molɔ̀ːn Labé Skýla~
As Bob Hagel would say"You should not use a rifle that will kill an animal when everything goes right; you should use one that will do the job when everything goes wrong."Good words of wisdom...............