bullet seating different force

Apollo

Apollo

Jason Stanley
Some of my bullets are taking more force to seat than others. Here is some of the info
30 BR
Wilson seater/Arbor press
annealed cases 5-6 firings ago
turned cases for an over bullet measurement of 3273 - 330 chamber(measured)
using a 323 bushing - for .0043 neck tension
chamfered and deburred each neck prior to loading

I can easily tell the difference when seating so have separated into 3 sections - very hard - medium - just right. I measured some out of each pile and the necks are "tighter" on the hard (3255-3260) and on the just right they are around 3275-3280.

When I measure a fired case with my chamber gauge it measures 1.233 and when I resize it it measures 1.232. Reason for telling you this is: if my shoulder bump is staying the same through the last 2-3 firings (bought a new resizing die before that) wouldn't that indicate I don't need to anneal?

Just wondering what is causing this? I am going to a shoot this weekend - and will test the 3 groups during the warm up - I am hoping each "group" will shoot consistent - if not, I have 40 or so that are in my "just right" group that I will have to keep reloading. Any help appreciated.

Stanley
 
IMO you are overworking your neck brass. May I suggest you shoot for only .0015-.002 interference.

And double check your neck thickness. Because of slight inconsistencies I've sometimes had to final-turn only after fireforming.

But my guess is that you're work-hardening your brass from too much movement.

hth

al
 
Jason, I'd take a look at the inner case necks.

When we neck these 6BR cases up, we assume the inner neck diameter is consistent and perfectly round after we're done. A little time spent dropping pin guages into the necks of this newly necked-up brass will show that's not always the case. Might be a pun there.....;)

For the last couple of seasons, I've been cutting the inside of the case necks on my 30BR's to a consistent diameter before neck turning. This has helped with bullet seating force consistency.

If you want, bring some new 6BR cases (just necked up...nothing else done to them) with you this weekend. I'll take 'em home with me, cut the neck i.d.'s. and mail 'em back so you can tinker with them and see if it helps. 20-25 cases would be enough of a number to give you meaningful test results.

This seems to be a bigger issue with these later Lapua 6BR cases than with cases from several years ago...at least in my experience.

See 'ya this weekend. :) -Al
 
Thanks to both of you for replying. Yes Mr. Nyhus, we will talk more tonight or tomorrow. Thanks again.

Stanley
 
Sounds like your turning is incredibly inaccurate, and you're over-sizing.
You didn't mention your method/tools for upsizing, or for turning.

Have you measured thickness variance in the necks?
Have you checked for doughnuts?
Did you turn at 6mm onto the shoulders, then size up a cal at a time? 25,26,27,28, then 30cal..
 
Neck Tension

I use a .325 neck die on my .330 neck 30BR, the loaded rounds measure exactly .328 over the gas ring of the bullet. When they come out of the die, the cases actually spring back to about .3255.

I am pretty meticulous about my cases, but I still get a few that feel kinda light when I seat the bullet. I just use them for a clearing round.
The strange thing is, the next loading, that very same case might have the same feel as the rest. I have no explanation for this.

What does concern me is your cases coming out of the die are a different size. Since I do not anneal cases, I would have no comment on that, but it is obvious that the hardness of the individule case necks are varying. Different hardness means that the metal springs back at a different rate, hence a different size out of the die, and a different feel as the bullet seats.........jackie
 
I am going to anneal this week sometime. Friday night before Sat's shoot, I did a little test. I shot 2 from each of my 3 groups(red-orange-green). 1 nice hole. This weekend's shoot went well, so bullet seating feel, isn't a huge concern for me shooting at 100/200. However, I still don't like the idea of things being "different". I'm going to try annealing and see what that does for me.
Thanks for all the replies

Stanley
 
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