From the research ive done alot of top f class and benchrest shooters believe leaving a light layer of carbon in the necks is beneficial and squeaky clean necks can be detrimental to consistency .
That's how it was back in the days I was shooting HBR. The carbon makes the tolerances tighter. Anything making tolerances tighter is better.
Usually, after a match, I would take some very fine steel wool, with a bit of sizing lubricant and and lightly wipe off a bit but not all of the carbon that had accumulated.
HBR is a bit different when it comes to reloading cases, as are other forms of match shooting.
The really anal guys are looking for reasons to blame larger groups or missing the 10X ring/dot. Consistencey is the holy grail.
I've seen shooters, both men and women that miticulously polished their case, cleaned out primer pockets , deburred the inside lip of the flash holes and uniformed all of the flash holes. Did it help them to win more matches???? Not that I could see.
The consistent winners were usually those that had a great barrel that had been chambered with a great reamer, on a good solid action, with a decent scope and trigger.
Sometimes, a particular gunsmith would get in a magic reamer, along with some extremely consistent barrels.
Then he would either rebarrel or make up as rifles as possible, while the cutting edges were still sharp enough to cut, without regrinding or sharpening, other than a very light stoning, if needed.
Those reamers would be sold off, rather than resharpened. Once they were resharpened????????????????????
Same goes for neck/throat reamers/pilots. I've seen pilots specially machined for an individual barrel.
Most benchrest venues involve the individual shooters turning the necks on their cases, so there is an overall clearance of .002
The necks are usually very thin.
Wilson dies, with interchangeable neck diameters were used by almost everyone.
Neck sizing only was the norm for the venue I shot.
Some of the folks had chambers that were right on or slightly below minimum spec. They full length resized every load.
That meant they had load up enough ammo before each match to make it through.
I chose not to go that route and loaded at the range, with thrown powder charges from a Lyman Ideal powder dispenser. These were consistent to plus/minus 1/10 consistent charges.
Anyway, only a very few insisted on polishing their cases.
I have a couple of RCBS and Bonanza Bench rest dies that have loaded hundreds of thousands of rounds.
One in 30-06 and another in 6.5x55.
Both of these dies partially resize the cases to about mid body, where they just reduce the shoulder diameter and set the shoulders back appx .003.
This set of dies has been used, without adjustment, to load for a few hundred different hunting rifles.
There have never been any scratches on a case, that weren't there before.
Now, if you like going through the time, expense, process of prepping and polishing cases, because it relaxes you or just makes you feel better, go right on ahead.
I find it about as helpful as turning the necks of cases that are already .020 smaller than the neck areas of a hunting rifle chamber.
