If they chamber hard it is my experience it is usually the shoulder not a trim length problem, although they may need trimmed as well. I use a hand priming tool and feel every primer seat to the bottom. The last batch of 100 I felt no difference case to case after 14 firings. There was still a good tight fit and they were all the same. Like I said these 100 cases were loaded with nothing other than 300 gr bullets and a most charges were 92.5 gr of H-1000. None less than 91 gr. I would seriously worry if I was shooting a load that loosened a primer pocket in a Lapua .338 LM case. The only failures I have seen from Lapua head stamped 338 LM brass was after many firings and it was from separation above the web. But this brass had long paid it's dues and was still holding accuracy, as good as most humans can shoot at long range.
Yes, the Lapua 300 win brass (belted) of long ago that was discontinued was made by Norma for Lapua. This is the only case I am aware of that Norma made for them, there could be others I don't know. But I was under the impression it was to Lapua's requested specs. This is good brass too but no where near the tuffness of Lapua 338 LM brass. I shoot this discontinued brass in my 300 win and it will not get near 14 firings before the primer pocket loosen. Maybe 7 or 8 firings would be more like it. I would assume it is the same strength as the Weatherby 378 cases that fail in 4 to 5 firings but the 378 obviously is under more stress.
None of this is news, it is old facts that I and many others here are aware of.
As I posted, I would be interested in buying some 3 X fired 338 LM brass if it has not been abused. I would assume the price to be fair for used brass, and want assurance it was 3x fired. If I could be given the load info that was used in it that would be great too. But never the less I would buy a batch under these conditions and then I would inspect and measure it prior to use.
Jeff
