This is true. I believe Norma made the brass for Lapua, and made the brass to Lapua's specs.
Correct. And I have a personal supply of Lapua stamped 300 win brass. I also have tested Norma to compare along with a gaggle of other 300 win brass. What I found was with the same loads the Norma will suffer from loose primer pockets a while before the Lapua does. Is that because the Lapua speced out the brass to be harder? Or just a difference in lot to lot runs? Your guess.
When choosing 300 win brass for a long range rig with heavy bullets one needs to consider case volume. Especially if H-1000 will be used. The lower volume cases will show pressure about 2 or 3 grains before the higher volume cases.
Here is what I have seen. RWS and Bertram have the same "lower case volume" but are tough brass and good quality.
WW, RP, and a few others are of a higher case volume, pretty tough, less expensive, but you will cull some when you do brass prep. WW brass has shown it will take the same loads as Lapua and shoot well if you take the time to prep and cull.
Graf is good brass and higher volume but hard to find also.
Lapua is of high volume, very good in quality, pretty tough but not as tough as other head stamps made by Lapua. Its hard to find and expect to pay $2 each or more if you even find any for sale. I get 10 firings or so from mine with a full house load before the pockets are getting to loose.
Norma, same case volume as Lapua but as with all Norma brass I have used you need to reduce the charge weight to keep the primer pockets usable for 5 or more firings. But good quality and consistent between cases.
Sorry none of my Lapua brass is for sale. I sold some new 300 win Lapua brass a year or so ago just to help a guy out and what I have left is to feed my 300 win.
If you are like me, and willing to dig, you can find some 300 win Lapua brass. But it wont be on a store shelf. Unless you find that gun shop that no one has been in for years. Talk to older guys at the ranges. I have found this brass was popular with some bench rest guys of the past who shot 300 wins.
But if you are looking for tough brass, what we can get today is RWS when available and Bertram for the 300 win mag. If you want some Bertram contact Dave300 on this site. We bought a run of it and I think he would sell some of his.
Hope this helps
Jeff