Although my experience pales with some here that have posted a response...my experience mimics the above. The neck tension on new Lapua seems all over the place.

A while back, I was shooting a known and tested accurate load at 600yds. I was having excellent results on windage but my vertcal was all over. I was actually chipping the t-post above and below the plate...

Thats when another member here introduced me to the Sinclair expander mandrel die. Here's a short article:

http://www.accurateshooter.com...ls-and-neck-tension/

Like much in this hobby, its a never ending learning curve. Im now playing with a .300wm that has a much better barrel and action than my .308 700 5R. I also have an assortment of brass for it including Remington, Hornady, Norma, and RWS. With the .308, I shot ONLY Lapua except for the first rounds down the barrel. Playing with all the different brass will be my next "300 level" education class in reloading. Lucky for me, I got someone who already experimented with it all to use as a guard rail.

That Remington is a great gun for a off the shelf rifle. It taught me a great deal about the basics of precision shooting and reloading. Im hoping this next step will add to my knowledge base.

I just always ran my new brass thru the Lee collet neck die before loading it.

Same principle I guess.

RMD

entropy, I appreciate your "300 level course" analogy. I am learning a lot too. I have kept a lot of data and it is interesting to review it now and see the wrong conclusions I came to based on factors that I didn't understand or was not aware of at the time.

While wasteful, for now it is just easier for me to fire form brass with surplus pulled projectiles and less expensive primers even though it wastes good powder. On the next firing, I get the results I expected and I can use the trigger time to practice fundamentals.

Perhaps with something other than a production barrel, virgin brass would be more consistent for me, but, as it is, I'll just keep on fire forming.

Henryrifle