I finaly got a crony and did some testing.
On my 7-08 the book said 3180 fps on my load and I got 3117-3098
close enough
My hornet claimed 27 something and I got 2750 fps
Put my friends .243 through it.
Load was IMR 7828 one book claims 3120fps with 45.5 gr and the other claimed 3000fps with 46 gr but this gun only shot 2817-2780 fps with 45.5 gr
seems awful low, any ideas

Barrel length is the first thing that comes to mind . Thier test usually state what barrel length was used to get them. Compare that to your barrel .

I can show you a thread where one man had several "identical" rifles and fired a lot of different ammo through each of them....

Roughly the variance from rifle to rifle with the same ammo was about 200 FPS.....

Reloading books are not as precise as we would like them to be...

Your mileage will vary.....and you and I will never know why!