Difficult Extraction...

Under loaded rounds also increase pressure.
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Also increase or can increase. There is a point in there somewhere when the primer protrudes, meaning the case head did not seat against the bolt face because the pressure was too low. Then there is the that event that renders the gun scrap and no one can do every time.

F. Guffey
 
Guffey, by "sticky bolt lift" I meant that it required more effort to lift the bolt handle than what I consider "normal". the first time it occurred was not substantial, but I did notice it... at the next charge weight it was more noticable (and I did not shoot any more of either weight after that). The bolt does cam back after the handle is raised.

Ammo, the scale is an RCBS 505 and the last time I checked it a few months ago it was right on. I'll borrow some check weights and check it again since you mentioned it, but I'm pretty sure it's still on.
 
Yesterday I had an issue with extracting fired cases. The bolt lift felt normal, but after the lugs cleared the recesses, the bolt handle was extremely difficult to pull to the rear.
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by "sticky bolt lift" I meant that it required more effort to lift the bolt handle than what I consider "normal".
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I thought you said the bolt lift felt normal. Difficult to extract goes with a difficult to lift bolt handle.

F. Guffey
 
Last year I had a problem with some cases being tight on bolt extraction. I had been neck sizing only. I believe the problem was that the cases had been shot so many times that some failed to spring back after the shot. I annealed and bumped the case shoulders back .002 and the problem went away. You can avoid variability by always lock the die ring when forming cases.
 
"...don't start new threads too frequently..." You start really good ones when you do though.
I'm thinking it's a tight chamber combined with max or near max loads thing. The latter can cause odd pressures in tight chambers. Just a WHAG though.
"...The 2.810" number is the SAAMI max..." And is not measured to the Ogive.
 
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