I've used 40 grain Nosler lead free for both my AR and Rem 700. Bug hole groups with Benchmark in both rifles. I've also used 50 grain Nolser lead free. I got 1/2 inch groups in my son's AR with Tac. My Rem 700 didn't group the 50s very well. The bullets didn't keyhole, but the groups were 1.5, 2+ inch. I believe the 50s need a 1:10 or maybe 1:9 twist to stabilize. My Rem 700 is 1:12 and my AR 1:9.
I"ve shot coyotes and ground squirrels with the 40 and they work quite well. Before the lead ban I was a 50 grain Nosler shooter and would have never considered a 40 grain bullet for coyotes, but these 40 lead free work just fine.
