Different seating pressures

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Cowbaby

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This is an interesting concept. I have always loaded like you thought where i don't add case lube to the inside of the neck on every round thinking enough would build up after a while or until I hear the ball expander asking for more. I think we all fight those occasional fliers with every idea imaginable. I seem to have them down to about 1 out of 5. I think I will start lubing every one lightly from now on just because, I just never liked the idea of lube inside the case anyway. Just anal I guess.
I think Retriever man is right also, a factory crimp die should negate variance in neck tension to some degree. I factory crimp all my rounds as they are going to get banged around and some shoved nose to nose in mags out of necessity. I also have to be more expectant of results with hunting bullets vs match grade stuff.

I am currently making seal-a -meal shrink packs of 30-50 rounds of 30-30 and others for long term storage as you see in the picture, I pick the plastic holders up at the gun ranges. I am using some old recipes that were decent just to get some of my older powder into some cases. It should store better this way and ready to go.This day and age pouring old powder on the roses is out of the question. HECK NO. Lucky for me I keep good notes on every grouping I ever shot in separate caliber specific notebooks as you see here and can just go back to stuff I did 20 years ago and pick the best charge..

Never again will Zhou Bi Den and Headboard Harris catch me in the middle of a hunting season with a 4-5 of rounds left passing on shots because you can't find any more . DONE with these clowns

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swampratt

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So you're talking about neck tension? Did you measure this by before and after case mouth measurements or what?

I measured all necks for ID measurement and for OD measurements.
If I have .001" difference I do not use that brass to shoot a group with in load testing.
In fact if I have a case with 1/2 of a thousandths difference I will not use it in load testing.

What happened here is I had Lapua cases and some were annealed and then sized and I had some others that were not annealed.

I thought I will just anneal the already sized cases and brush the insides of the necks and load them.
I began loading them and WOW the pressures to seat a round were very high.
I took a few of those cases and ran them back through the Full Length sizing die and brushed the insides of the necks again.
Seating pressures were lower.
Those got mixed in with the other Lapua cases and I felt the differences in seating pressures.

I do have a small valve spring pressure tester I can use and see exactly what pressures are when seating.
I do not use it except for experiments or valve springs.

I will agree Lapua cases have very even seating pressures and even after dozens of reloads the seating pressures are
almost the same as once fired.
This is without annealing at all.

But i have shot groups with the same load with annealed Lapua and not annealed and I get tighter groups and minimal fliers
with annealed each time Lapua cases.. same goes for any brand case I have shot.

I have tried .001" neck tension(interference fit) .0015" .002" and .003" I have found .003" works best for me and my guns.
I do not crimp.
I tried and it did not help my groups any at all.

I also tried .004-.005-.008" neck tension and those just work the brass in a negative way.
Too much and you remove some of the spring back because you are removing the annealing benefits.


I will explain that a bit.
At .008" neck tension seating the bullet took a lot of pressure but as the bullet base got past the neck and into the shoulder
the seating pressures dropped. and it dropped below where the .004" case was at.

So I removed the .308 bullet from the case with an inertia puller and measured case ID it was .0005" smaller than bullet OD.
So .3075" ID
The .003" interference fit would have .001" interference fit after pulling a bullet and the .004" was sometimes .001" and sometimes less. So .004" was a bit iffy.

If crimping works for you guys then by all means add a crimp.
There are dozens of ways to get there.
 

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