Does Cases Grow Longer when Sized?

[Reloader222]

I am using a comparator to measure my .270Win cases before sizing fired cases. The "value" up to the shoulder of the case measures 2.0275" after firing. When inserted in the chamber the bolt closes it bit stiff. I setup the Redding Full Length Size Die to make contract with the shell holder and then I turn it a ¼ turn out as to prevent it from bumping the shoulders back too much. BUT after sizing it the case now grows to 2.0310" when measured up to the shoulder. When chambering the case in the rifle, the bolt closes still as stiff as before. When I turn the Die in to contract the shell holder as per the instruction of the Die Set, it had caused dents on the shoulders of the cases (along with too much lube). I had now solved this by applying Imperial Wax only to the tip of the case neck and to the body. No more dents. When measuring the case now with the comparator, it measures 2.0280" up to the shoulder and the bolt of my rifle closes easily when chambering the case. Your opinion is highly appreciated.

 

[Catbird]

Does your expander button drag hard on the way out?
You may need to lube the inside of the cases with mica.

Just a guess, I'm not there.

 

[Bart B]

Yes, if you're measuring head to shoulder length, or case headspace. As the case body is sized down that pushes the shoulder forward. If the die's shoulder doesn't stop it moving forward, then it will have longer case headspace than when fired.

Fired bottleneck cases should have their shoulders set back about 2 thousandths for best accuracy and case life.

If the case headspace is too much and the bolt binds when closed on one, the bolt won't lock up in the same place for each shot and accuracy suffers.

1/4 turn on your die changes it position in the press about .016". There's about .072" between its 14 threads per inch; 1 divided by 14 equals about .072. Copy then print the following actual size and the labels should fit your die lock rings.

 

[Reloader222]

The expander ball does not drag when the case exit the die. I think Bart B has the answer for me on this. Many thanks for the photo - I would definitely use it!