With the limitations on acquiring various powders, I have been looking into available smokeless loads for some of my BPRC rifles.
I have the current Lyman Cast Bullet Manual which has been a great resource.
My question is in regards to modern Ballard (Cody) Rifles.  What should be considered the upper limit for pressures in these newer guns?
The Lyman book lists pressures, but I'm not sure what the Ballard cut-off should be.  Specifically for the 40-65 WCF cartridge.  I typically shoot 300 to 400 gr. slugs if that matters.
Thanks!

Although the Cody Ballards were made with modern higher quality materials, I'd not push them very hard, or much harder than original forged receivers. The design is still the same, so likely they would fail the same if overloaded.
I consider loads over around 24,000 psi to be too much, and I keep all mine below 20,000 psi chamber pressure. I use a lot of H4198 or IMR4198, and it's extremely low pressure with my ballistic program showing my loads at or below 12,000 psi.

I used 21 grains of 5744 behind a .410 Jones Bullet.