Question on Brass

[Bundah]

Hi

I am using Lapua 6BR brass and have fired the brass 3 times.
The necks have been turned and when loaded the neck measurement is .2675
A fired round neck measures .269.
I full length resized the brass and measure the neck and get .265
When I seat the bullet into the resized brass in 2 pieces of the brass the projectile slides out (no neck tension)

I assume I need to anneal the brass or do I just accept there are a couple of bad pieces of brass and throw them away? Is this normal for Lapua brass?
I shoot 105 VLD Berger's over 30 grains of Varget (AR2208).
The load shoots an inch and a quarter at 500.

many thanks

 

[Steve Blair]

I anneal my Lapua 6BR brass every firing. My measurements are similar to yours. Chamber neck is Ø.269", loaded neck is Ø.266" and is resized to Ø.2645". I do not experience any loose necks and all feel pretty similar when seating. Your proposal that they may need annealing sounds reasonable, although I would not think necks harden that fast. The reason I anneal every firing is to ensure that all cases are in the same state each loading. So far, it has worked pretty well. My current lot shot 450-40X in a recent 300 yard match and was the twentieth firing. I shoot 105 Hybrids over H4895.

 

[jonbearman]

What is the neck measurment of the chamber to begin with?Some how it doesnt add up,if your neck measures 269 after firing I would think a 265 bushing would give you more than enough tension. What is the id of the sized neck? Maybe the bushing is mismarked.Are you sure the 2 you have problems with were sized or did they get cut unsersized.It just doesnt compute.

 

[RonS]

Try measuring the thickness of your case necks, it sounds like those two may be thinner then the rest. Just my two cents of an opinion.

 

[Bundah]

Hi

The chamber is .270 and yes the brass has resized.
To check I expanded both necks and then resized them again with the same result.
I am using a mitutoyo micrometer to measure outside neck.

The neck wall thickness is 0.0125

thanks

 

[timeout]

Your measurements all sound good. I am guessing you are not using a bushing die. If you were, a .265" bushing should be fine. I anneal mine every firing, but don't think three firings should be causing the problem. If you send them to me, I will anneal them, run them through a bushing die and see what happens. I would be very interested to work with this and try to find out what is wrong. Also, what does it feel like when you seat the bullets? This is why I like Wilson seating dies and an arbor press to get a better feel for the amount force needed to seat the bullet.

 

[Bundah]

Hi Timeout,

I am in Australia so sending them to you is probably not going to work.
Just to let you know I went to a mates place last night and annealed the brass.
When I get home tonight I will expand and resize the brass and see what happens.

thanks

 

[timeout]

Hi Timeout,

I am in Australia so sending them to you is probably not going to work.
Just to let you know I went to a mates place last night and annealed the brass.
When I get home tonight I will expand and resize the brass and see what happens.

thanks

Well, I could fly over with the Benchsource annealer and we could go kangeroo hunting afterwards. ;D