If the cases are so important to the work in a breech seated situation, why haven't the 'records' been set by a fellow using brass turned from stock? Such cases would be identical and much more concentric- or, is it elsewhere the problem lays?

Both NBRSA and CBA fixed ammo shooters have told me they reject about 75% of the cases when testing a new lot. 

Back in the early 90s after I shot my first 250 I spent a couple years testing every factor I could think of trying to duplicate it.  Most critical was achieving consistency with the offhand stock and especially the 3” prongs on my Ballard.  Shooting enough to maintain that consistency, I eventually discovered the single most critical factor to be the age of the lube on the bullet. I always shot with a single case loaded at the bench.  I did not find any inconsistencies breach seating with multiple single cases indexed but I did not test random orientations. An occasional misoriented case did not cause any noticeable differences at the target.  

I do not know what brands they were referring to, but I spoke to a BR guy at Tacoma on Friday and the CBA shooter at Kenmore yesterday.   

On Tuesday there was a CBA military shooter fire forming Lapua at Puyallup getting ready for the CBA Military Nationals, but we did not discuss case quality.

When I recently shot the 250 with the 28 the lube had been on those bullets for eight months BobZ. I tend to think the choice of lube might have a direct bearing on shelf life and any loss or possible gains in accuracy. That was actually untypical of me I fell  ill and did not shoot for those eight months. I always try to lube a few a days before being used and I was a bit concerned. On the other hand during the off season I used to try and cast enough bullets to get me through a year of matches and practice and typically around 2500 and I never noticed a difference nor were there ever enough cast to make it all the way through. I would then just pull what I felt I needed for the occasion off the shelf and then lube them and any left overs went right back into the pot. The reason for doing so is I am very adamant about shooting in the order as cast and they would all be so marked. 

JLouis

Dellet my cases for the 28-35SS are 25-35 cases necked up and trimmed. I should just go ahead and dial in a case on my lathe and turn a neck. I have an attachment for the cross slide so I can bypass the tail stock that gives me the ability to make the adjustments to have the case setup to be running true prior too. Now trying just trying to figure out how many I should do after going through all the effort to set the lathe up and not having to do so again should they make me even more happier than I already am? 

JLouis

JL, My own lube a year or 2 old is the only one that comes close to shooting 250's.  I have experimented with Jerry Hartwig's lube and Alberta Schuetzen for lubes I can put on and shoot without aging.  The jury is still out. Dell 59C does not work in this rifle.

BTW, My cases are original Winchester 32-40.

BobZ strange in that the 59C hasn't worked for you? I found it to be far one of the best lubes I have used and the only reason I no longer use it is do to having the entire lower row of bones removed from my right wrist and it hurts like the dickens to say the least when trying to push the bullets out of the lube cake when fully set. What I now use and have since the surgery back in 2011 is 75% Javelina Schuetzen Lube purchased from Jerry and 25 % Dell59 C. It is noted as JJ250 on my equipment list and or tagets and stands for John and Jerry's 250 Lube. It started out 75 Dell 25 JSL, 50 Dell 50 JSL and finally 25 Dell 75 JSL to fit my now not so painful needs and it works very well for me in more ways than one. 

JLouis

I have mostly formed brass cases, but also have a good amount of RMC lathe turned brass. I was told by RMC to anneal cases prior to using them and did so for the top half of the cases. I have numerous loadings on them with no issues at all with case mouth or primer pocket failures. They seem to work the same as my formed cases do so far.
Unsure of the age of the RMC brass I have as it came with guns I purchased as new brass.