SteveB:
In 1996-7 the USMC Teams at Camp Perry work tweaking out their loads for the NM Course of fire (I used to shoot these matches 20 years ago). They were using the 175 gr Sierra MK with fabulous results.
UNTIL (drum roll please....) they experienced op rod battering and subsequent damage. Great experiment and results indicated that the M14/ M1A's like 168's as an upper limit for bullet weight. The US National Match course of fire only shoots up to 600 yards. Many Marine teams were competing up to 1000 yards, The Wimbledon Match or something like it.... with the 175 MK's until the op rods began to separate. Now the USMC happens to have a larger budget for op rod replacement than Skullboy and I combined. So I ain't in a hurry to shoot my Norinco M14 Douglas NM bbl'ed at 1000 yards with iron sights. I'll use my Remmy VS or StealthII with 175 gr. MK's for that distance.
In 1997, the US ARMY AMTU teams trounced the USMC Teams with their M16A2 (Mouse Guns) shooting the 80 gr. VLD bullets from Compass Lake, HART, Krieger , Obermeyer, or Douglas barrels.
All of this information can be found in John Feamster's book (I've got it downstairs....) "Black Magic" .... Here's the link:
http://www.compasslake.com/Black Magic.htm
This book is an excellent read and almost the definitive book for long range shooting with yer black rifle (not to be mistaken for the short barreled family of door-kicking entry M4's et al).
In this book, John Feamster uses an M1A and M14 to obtain his "Distinguished" badge if I recall correctly, but he goes on to support the Mouse gun throughout it's ascendance at Camp Perry's National Matches and the resulting retirement of the beloved M14 (until OIF.... yuk, yuk, yuk)
Cheers (and I hope this helps)
Barney