These P 45 Auto Rim loads use high quality Starline brass with flashsuppressed powder to shoot in the dark without blinding yourself. Both of these loads are the equivalent of P 45 ACP ammo also known as 45 Super. These are very stout loads but will not harm modern 45 ACP revolvers nor will these loads harm any postwar 45 ACP revolvers. Feel free to safely shoot these loads in any post war 45 ACP revolver in normal good operating condition.