Re: pressure signs at 1 grain over books starting load
One, the rate of twist isn't sufficient for a 300 grain pill and two, my loads chrono at around 2800 FPS with the 2650 SMK loaded 20 off the lands in Lapua Brass (sometimes PPU) and everyone is crimped with a Lee 338 Collet crimper.
If I load at COAL (3.68 SMK or 3.575 SGK), the FPS don't change appreciably.
I say around because I use my buddy's chrono and it's an old one. Never been a professor of speed. Speed kills, kills rifling.....
Maximum recommended load with a H1000 for the 250 SMK/SGK is 100.1 grains btw.
My feeling is you'll do better with a 250 versus a 300 but it's your dime and rifle, not mine.
The 338 Lapua Magnum is a very touchy caliber to load for as many will attest to on this site (and others).
I found my sweet spot, but it may not be yours.
I'm more concerned with what the pill hits, not how fast it gets there.
There is nothing that a 338 Caliber won't decimate in North America at even the starting loads, so why push it.
You obviously have some issues, what exactly they are, I have no idea because I'm not there. I'd start with good brass and review your loading practices. Something isn't right in your procedures, what that is, I have no idea.
'It's not about me
, it's about we