Click on extraction?

[Kodiak99317]

I just got my hands on some new Norma 6XC brass. Necks measure very consistent as does the new empty case weight. I have found via smoking a case that the only area I have to size the Norma 6XC brass in is at the base. My chamber/case (6mm - 250, 30 degree shoulder) is based of the 250 Savage case as the parent with a .465" base and the 6XC has a .467" base (best I can measure with calipers).

I have a modified, cut-off 250 sizing die (only has the .320" of the very end of the original 250 die, just enough to go into the press with about 2 threads to hold it in place) that sizes 1/2 the case body down to the base. The new base diameter is .466" but a chambered empty 6XC sized with the above die makes a click sound when I extract it and I have to use a hair of leverage to extract the case, were it makes a "click" sound to get the bolt to open enough to move it rearward. I fells good going in, with just a hair of pressure needed to close the bolt with the firing pin removed.

Any Ideas what is making the case extraction go "click"?

 

[maynard]

Primary extractor on the rifle? This is the little ramp the bolt handle hits when lifted to start the extraction.

 

[NormB]

Kodiak,

Click on extraction occurs when the base is tight in the chamber after firing. As Maynard says on primary extraction. Hard bolt lift occurs when case length stretches. In my experience Norma brass is softer in the base than many others. I have been told Norma uses one more annealing step in their brass manufacturing process leading to this softness.

Only way to get rid of click with Norma brass is to reduce load to not expand the base, or resize the base much smaller, and hope it doesn't expand too big in chamber.

NormB

 

[Kodiak99317]

Yesterday I cut off the end of a 308 SB die so I had about two threads to hold it in the press. Next I drilled out some of the upper end of this remaining piece of SB die. This "short die" sizes the *NEW* unfired Norma 6XC brass down enough in the base area (now down to .462") so there is no click now on primary extraction. Still have to polish it up some as it scratches the brass pretty good, but she chambers nice and extracts without any issue now, then size all of what I have for my 6-250 30 degree and go fire form it. Maybe I will wait until this barrel goes south before I fire forming these 400 pcs for Norma 6XC into my chamber. My barrel has approx 3000 rounds down her now and I want to get another 1000 or so thru her if she will hold under 1/2 moa, if not this existing barrel becomes the fire former barrel and I will screw a new one on.

Thanks guys.

 

[Kodiak99317]

Here's the final product. Used my cut-off 308 SB die to size the base down (you can see the darker area of that is sized down, about 1/2 way down the case to the base and this eliminated the "click"), then a 260 mandrel to neck it, then thru a 6BR die to set the false shoulder. The last case is a formed 308 Lapua case also made into 6-250 since I have not fire formed any of the 6XC cases yet. Using the 6XC as a parent, there is a lot less work in making the 6-250 30 degree shoulder case. My case is a hair longer than the 6XC and has a smaller base size, otherwise, it is the same case.