Lapua 6.5 CM Brass

[esoxecosse]

I've just started using a box of new Lapua 6.5 CM brass and have noticed a problem with it, with new brass (Lapua) I normally don't do any prep work with the brass other than length and chamfer and deburr and fix dented necks, primer, powder seat bullet and go.
This is the first time I've had brass in the cardboard box and I've found it takes much more pressure than normal to seat the bullets and I'm getting inconsistent seating depth on occasion, the O.D of the neck is 0.290" just the same as my other brass and the wall thickness the same (0.014"-0.015").
I've put the remainder I have over a 0.2625" expander and a 0.262" expander fits tightly inside the neck. the unusual thing is the O.D remains the same at 0.290".
To me it's like the brass hasn't been annealed properly and is hard.
Have any of you come across this ?

 

[One on top of two]

I have always run my new Lapua brass through a mandrel before a first fireing, with case necks dipped in graphite powder to smooth the whole process out.
The issue you mention is the same with 99% of new brass from batch to batch

 

[esoxecosse]

I understand what your saying and have just checked my notes because my memory isn't the best and I did indeed put a 0.262" expander through the whole box with dry neck lube when I got them in May, funny thing is not all the cases from this batch are the same, some have been fine, I tried 3 x cases from another already fired and annealed batch and they were perfect.
I haven't noticed the batch to batch issue you describe and I have a few different calibres but this is the first batch I've got in the cardboard container.