I can't shoot any form of comp that does not concentrate on a stationary firing discipline, primarily because of age and medical issues. But those every conditions may give me an edge when trying to figure out how I might go about configuring a rifle to do such things, given my own personal drawbacks.
First, I would value portable and wieldy at the top of my list. To meet that, I'd draw the upward weight limit at around 8-9 pounds. But one does not need to be in my boat to find this limit desirable.
IMHO, barrel weight adds advantage in sustained fire, and not much elsewhere. Throwing in mass absorbs heat, and radiates it slower. The slim barrels shed that heat faster, carrying no heat overhead to the next stage. Unless courses of fire involve strings larger than 5 rounds at a time, I believe extra barrel mass is not helping.
I took 4th in the NJ State Sniper Championships in 1997 with a Winchester Model 70 Featherweight .30-'06 mounting a Weaver V-16, and a Harris Bipod. I fired FGMM 168's. Clearly not the same sort of comp as much we discuss here, I think that M70 would have been even better suited for what most run-n-gun tactical type shooters engage in here at SH.
I personally believe that although a heavy barreled range queen with some effort to harden it for rough handling has been the norm for literally decades in the tactical community, its probably not the really, very best way to go for something that is really a hunting application.
Good accuracy is not solely the province of the LR match rifle, as my older .30-06 Featherweight has repeatedly demonstrated in tactical competitions. Good ammo, good skills, and good, but lightweight rifle components can also deliver the mail when and where needed.
What they can't do is hold a position in a sustained firefight. But if that's where they find themselves, then the entire situation has gone pear shaped (Infantry, and not tactical); and the heavy barreled LR match rifle is still not the better choice among those available.
I just really think that some decisions made decades ago about the direction of Tactical Operator employment needed to take have come too far on down through those decades to burden and overload that operator, and unnecessarily so. What I think is needed is a basic, rugged, lightweight hunting rifle with medium power variable optics, and adding a sling and a Harris style bipod would be my favored choice.
If recoil management under sustained fire has become a requirement for the Tactical Operator's mission, then I believe a strategic mistake was made somewhere. If sustained fire plays any role in the SWS acceptance regimen, then again, a strategic mistake has been made. One shot, one kill is not about sustained fire.
And the .308 was never the right chambering for anybody's purposes besides Supply. Go either up or down in chambering to favor the longer end of the trajectory. I like the .30-'06 or .260 for that role better. Going with the big Magnums is also a mistake. Non-human target destruction is an artillery mission, where the Scout Sniper performs the forward observation role.
Maybe not what folks here might want to hear, but maybe still worth listening to.
Now, then; for the stationary sustained firing role, the heavy barrel becomes the desired component. However, it still comprises a thermally saturated heat sink after some sustained fire. The thermal burden takes far too long to equalize with ambient, and is not an advantage. Some of the recent advances in thermally conductive 'heavy' contour barrels probably offer significant advantage on this front. Better to shed heat rapidly than to accumulate it indefinitely.
And weight is not something I will ever again look forward to. At its 11.34lb loaded weight, even my old M-14 was unnecessarily heavy and I carried that sucker 24/7 for 13 months in a war zone. As a basic rifleman I could do effective damage a 500 meters with it that few occupants of the battlefield can do today. What I'm saying here is that not all of the thinking behind today's war fighting role may work as well as was common in earlier, simpler times. At 6ft Plus and fully equipped to come ashore, I still weighed under 250lb. Try finding that today.
And don't get me going on my Sweetheart Garand... Heavy, yep; but don't be on the downrange end of the trajectory. 600yd is just spittin' distance...
Wrapping up, this post may seem to have gotten rather far afield from discussing match rifles. But for the tactical competition, should it be?
Greg