Thanks guys, with this feed back I think I am going to order in a few hundred cases to really test in all three chamberings. My final decision will be based on the following:
1. If the brass will offer good brass life with current standard max load levels for my wildcats. If there has to be a reductiion in load performance, no reason to do it. In the 338 AX anyway, it seems that the Jamison brass will run with the Lapua brass with similiar case life which I want at least 5-6 firings with top end loads. The more the better but in my opinion, this is acceptable.
2. If the Jamison brass will be comparible as far as case volume and case weight consistancy with the Lapua which this limited batch of test brass seems to be very close.
Will this be a money maker, NO, the 338 AM and 375 AM correct headstamped brass is not a money maker either but its something I wanted to offer to my customers. Anyone can have a wildcat made but very few smiths will invest to offer correct headstamped brass to customers. Not a requirement, just a bonus.
In all reality, depending on cost, the 7mm AM would likely be the first to be done because there are the most of those out on the market but the 338 AX is catching up in a hurry and then the 300 AX would likely be third.
Again, thank you for your imput guys. This in no way would mean that you would be required to use this brass as the Lapua would still be perfectly functional in all my wildcats based on that round. This would just offer another option especially for those traveling over seas with these rifles.