Congrats on the shooting! Sounds like you had a nice day at the range. I had my first +500 yard steel hits a few weeks ago. Practice makes it come easy. Your groups will tighten up with the aid of a rear sandbag. I'm no pro, but I noticed a big difference in group size due to rear bag.
^^I just re-read your post... that target was at 1150...That group i nothing to be ashamed of for your first outting!!!
My 300 ultra with 185 VLD's produces a nice loud "Whack" on steel at 500, but doesn't put quite the "dent" that your Lapua makes.
What kind of steel you shooting at? That Lapua made it look like a license plate.
Again, congrats and nice shooting!