Hi Kelly!
We finally cross paths, AKA "Sparky" at Huntmasters. Are you using your "Machine Gun" for those loads? LOL.....
At 26.2 grains of VV N550 in Lapua brass and with the 40 grain NBT's, the best I can get is 4115 fps and that's at max pressure, just short of leaving ejector marks on the case head and with a little effort to lift the bolt after firing. I didn't set this caliber up to be conservative. I use to load two different weights for warm/cold days, not anymore.
I find the VV powder a bit temp sensitive, especially here in the desert with the wide temp swings from early mornings to warm afternoons. It seems to be the fastest powder, so I put up with it.
I started out with Don's 38 grain bullets. Tried both the 7 and the 9 Ogive and both failed 50% of the time, would simply "splash" on Coyotes. I was getting 4300 fps using PMC brass with those bullets, what a difference a couple hundred feet per second will do compared to your performance. Maybe his bullets are a bit tougher now? It was 6 years ago when I tried them.
I also tried Berger's and Blitz Kings in 40 grain's and a couple other custom bullets that where suppose to be "bonded" with the same poor results. Wouldn't think of using V Max....
Enter the NBT's with their "solid base". I'll get a splash once in a while on a shoulder hit but will still make a quick kill, I'm convinced the base remains intact and continues through, splash or no splash....
I've seen the difference shooting P-Dogs and Rock Chucks with the Ballistic tip vs. V Max and Blitz Kings, those two are much more explosive. If it wasn't for the Nosler's, I'd be "SOL". They group well too, under an inch at 200.
Gary