I have 2 Grendels. One with an 18" the other a 20". With identical loads the 18" is 10 fps slower than the 20". Benchmark is the powder of choice for both of those rifles. Both are sub MOA with multiple loads and bullet weights. Plenty for deer out to 200 yards. Light recoil so the wife and grandsons enjoy shooting them.

Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.

Thomas Jefferson