RE: New Tikka-What Ammo?
I've used Winchester (Premium) Supreme "Fail Safe" in my Tikka T3 .300 WM. I'm thinking of trying the same Winchester Premium ammo with Nosler Accubond slug this year. I definitely recommend if you're shooting over 150 yards to use the best ammo that will give you more consistent patterns in whatever rifle you use.
Some ammo will shoot better than other of same bullet gr and type for whatever reason (e.g. type of powder, manufacturing tolerances, etc.)
The Fail Safe Winchester ammo shoots consistently from a bench rest for me at 100 and 200 yds. in this rifle with good quality scope at the 1 MOA. It's stopped Elk in their tracks for me on several occasions.
I'm only thinking of trying the Nosler Accubond, both because I've heard a lot of folks recommend, the boattail slug seems to give very good flat trajectory/accurate shotfarther out and I like the look of how the slug holds together and expands.