I believe the IMI M855 is made to US military/NATO specs, and it has been approved and actually made for US Military purchase and use. So it should produce the same, or very close the same, ballistic performance as M855 made at LC. At least that was the way it formerly worked. There were similar supply arrangements made with other foreign ammunition manufacturers. There is a name for that program but I do not remember what it is. Idea was that if the US military got involved in a shooting war, say in Albania, it could immediately procure a large stockpile of needed small arms ammunition from an approved source, such as from a manufacturer in Germany or Sweden, that was much nearer to the action if it became necessary.