I went into the arsenal with nothing but ace, RHS, and 3cb loaded and found what you said was mostly true, as the 3cb M14 did the same damage as the RHS one since they had the same barrel lengths. I compared the G3 with the SCAR-H standard and short, and the G3 had similar damage to the CQC, with worse damage than the standard, even though the G3s barrel length is ~18 inches while the CQC is 13 inches and the standard is 16 inches.