Someone please explain to me why 55gr Hornady SXs on top of 26.0 of BLC-2 in new LC brass will not shoot out of my 1 in 9" twist barrel of my AR. EVERY other bullet I have shot, and every LOAD I have tried in the past 4 years, has shot into a reasonable group at 100 yards, with most very near 3/4", some close to 1/2". I loaded these like other 55 grainers in new military cases, on the mild side, but I cannot hit the 5 foot by 5 foot backstop at 100. Switch to any other bullet and groups are back to normal. This ammo DOES shoot well in a friend's AR with the same twist. I am going to give them away but really would like to understand WHY this is happening. ?? Also, at 25 yards the bullets hit sideways, so they are doing funky things on the way out. But I would like to know WHY, or HOW, this is happening with only this one particular bullet.