There you go again with your "explanations"..... You say the gunsmith "was wrong" because "your fired cases were .274." Then you make statements about "turning another two thou off and STILL having extraction problems".... can't you see that this means one thing really obvious??? IF TURNING TWO THOU OFF THE NECK DOESN'T HELP THEN NECK THICKNESS IS NOT THE PROBLEM!!!! What, do you think the NECKS are "hanging up in the chamber???"
Necks DO NOT hang up and cause hard extraction, ever. They cannot.
I run dozens of chamberings with less than .001 of total clearance, some with NO clearance at all, slip fit.....and the pressure difference between slipfit and .002 or .004 or even .008 clearance is ZERO.
There is no "minimum" neck wall thickness...... You can turn the necks down to tissue paper if you want, this has no bearing on anything. Around .260 necks are about the commonest 6MM thickness in the target world. Conversely, thick necks DO NOT raise pressure unless they're crimping.......Excess pressure comes from either too much powder or a bind somewhere in the system, thick necks can only cause over- pressure symptoms if they're actually crimping onto the bullet. And the only way they can be crimping onto the bullet is if you're forcing them in. The force required to crimp the bullet is very noticeable, it doesn't "just happen." If your necks actually were .002 larger than the chamber (because "the gunsmith was wrong") YOU COULD NOT CLOSE THE BOLT.
period
I don't care how hamfisted you are you WILL hesitate before hammering the bolt home on a .002 over-sized neck...
LONG necks now, it's more believable that you could force them closed and create pressure. Forcing the bolt home is stupid, but forcing the bolt home on just the end of the neck is conceivable.... And excess pressure will cause extraction problems. Read this again, EXCESS PRESSURE causes extraction problems because it swells the brass up at the base. The only way necks can be related is if they, the necks are causing the excess pressure. And the only way necks can cause excess pressure is because they're being crimped onto the bullet by the neck.
IF (and this is a big if) IF your problem is neck related then it's most likely that your necks are too long, that they need to be trimmed back, but YOU NEED TO ESTABLISH THIS. Many tight-nekkid guns are also set to be trimmed shorter than spec, just to prevent idiots from forcing the bolt home and blowing their face off. But you need to establish this, if you're creating excess pressure by forcing a crimp onto the bullet you're overriding the built-in safety features somehow.
Actually, you need to slow down and establish all of these things before you hurt yourself. You're getting all fussy again and not listening. You're not questioning WHY there's a pressure problem, you're not even accepting that it might BE a pressure problem. You just keep jumping to conclusions, WRONG conclusions regarding neck thickness and it's effect.
Now, if it's not a pressure problem then the next culprit in hard extraction is that the rear of the chamber is too tight. 90% of all extraction problems can be traced to this. Sometimes a "small base die" will help this problem but most often not. In most cases the fix is to enlarge the chamber. Reading your posts where you say there are no ejector marks, no enlarged primer pockets etc lends credence to your argument that it's not a pressure problem. But I must state again, THE NECKS ARE NOT HANGING UP! If the necks are involved in any way, it's to produce excess pressure.....So if you are NOT having pressure issues and the cases are still 'clicking' or sticking in the chamber then the problem is simply too small a chamber. This is very common. IMO 90% of all the custom chambers out there are too small.
ZERO extraction problems are because necks are hanging up in the chamber.....bases hang up, necks do not.
So..... if you really want to back off and find out what's going on then you need to trim some cases back, lop about 30-20thou off so you KNOW the necks aren't binding. Go ahead and turn them as thin as you want, turn them clear down to .268 AND SHORTEN THEM..... but get the necks OUT of the equation and see if your loads still bind up the gun. And back your bullets off the lands. Make absolutely sure you have zero resistance up front and see if the problem goes away........ YOU need to eliminate variables on YOUR gun.... what worked for someone else may not work for you.....there are plenty of guys here qualified to help you eliminate the variables until you find the real culprit but YOU have to follow through, step by step to find YOUR answer. Many of us here, myself included, have had all of your listed problems, several different versions, and many different fixes depending on WHY the problem. And through the process of elimination of variables we can bring you right down to the root of YOUR particular circumstance if you'll listen and take the step-by-step approach.
Or you can just keep on listening to the people guessing......and chucking parts at it.
it's up to you.
We will help if you will listen.
And in the end there will be ANSWERS, not guesses.
And we haven't even gotten to some of your problems...... your statement about "NOT on lifting the bolt up but on rearward pull of bolt" indicates another whole problem regarding your primary extraction......There's a ton of usable information in your posts.
al