Kirby I am very comfortable reading pressure in Lapua brass. I have lots of experience with the 300 gr bullets and the 338 LM. My last one I ran full house loads and got 15 firings from the brass and all primer pockets were still tight, all 100. That rifle is still going strong holding 1/2 mos to 1500 yrards plus.
The first signs of pressure in Lapua brass will show up with a flat face of the CCI 250 primer. Next will be a slightly muffin topped primer and at this time the faint shadow of the ejector pin bore on the head stamp. This first sign of stamping we see with the use of a magnifying glass. Then if you keep pushing the pressure up the pin stamp will become more evident along with a slight firmness of bolt lift on the second or 3rd shot.
To answer your question directly, no I have not used Norma brass. Shawn, however did the initial testing of this rifle with Hornaday brass. The Hornaday is equal in case volume to Lapua and I believe it to be softer. I am not sure who makes it for Hornaday? Norma? Not sure?
If I were not completely comfortable with the level of pressure being safe I sure would have not let several member from this forum shoot the rifle at the last Townsend shoot. They all seen my ammo box of fired brass, they all felt the smooth bolt lift even after a couple shots. They also watched and spotted for me while I took a few rounds from the same box and whacked a rock 1/2 moa tall at 2272 yards. My dial up was on with an inputted MV of 3198 fps in Bryan Litz AB program. This velocity was also verified by my Oehler 35 and my magneto speed
as well as Shawns magneto speed.
Thank you for your concern, and info., it is appreciated.
Now Kirby, I am going to rib you a bit.
DUDE!! It's the patented +P chambering.
Shawn and I did the math before Shawn ever agreed to build this chambering for me. We were counting on 3150 fro a 30" tube and hopeful for a little more. The addition of the 32" tube and N-570 pushed it to the max velocity we hoped for, 3200 fps.