Unexplainable high neck tension after annealing

[vonb]

I'm a at loss of words to what I experienced yesterday while reloading. I was reloading some 175 SMKs in Lapua .308 brass yesterday when I experienced some unusually high neck tension. This was with Lapua brass that had been shot 6x and I had just annealed the brass using the Hornady annealing kit. One thing I noticed was that when I dropped the brass in normal tap water after annealing, I noticed it left some gray/dried lime looking scale in the primer pockets. I then cleaned them out as well as running a bronze brush back through the necks after drying. The neck tension was so high that it was leaving a pressure ring around the tip of the bullet to which I have never experienced this before while loading this setup. What am I missing here? My steps were as follow:

- tumble brass
- resize brass,using Forster press and F/L Forster sizing die). Nothing special here....Been using the same setup for 4 years.
- clean primer pockets
- clean lube from brass using alcohol and cloth
- anneal using 475 deg. Tempilac from Hornady kit and then dumping in tap water
- clean lime scale from primer pockets and brush necks using bronze brush
- seat primers
- charge with powder and seat bullet

What am I missing here?

 

[alf]

I'm wondering if you are annealing enough?

Try full length sizeing after you anneal instead. You'll have to adjust your dies different, as there's not as much spring back.

Here's my procedure:

Tumble
De-cap only
Clean pockets
Anneal/quench
Blow dry outsides dry in a strainer
Full length size
Trim, chamfer, buff inside the neck with brush and steel wool,when needed)
Tumble again, which cleans off the lube and dries the insides,no more scale in the pockets)
Prime, load, and shoot
Repeat

 

[Silverfox]

I'm no expert, but from what I read, 475 degrees won't get the molecules of your brass moving enough to properly anneal the necks. According to the information I received with my Ken Light auto case annealing machine, you need to get the neck temperature up around 650 degrees.

 

[vonb]

With the Hornady kit, you place the 475 Tempilac 1/4' below the shoulder. Therefore, direct heat shouldn't be hitting this area. The temp. at the shoulder junction should be higher.

I'm no expert, but from what I read, 475 degrees won't get the molecules of your brass moving enough to properly anneal the necks. According to the information I received with my Ken Light auto case annealing machine, you need to get the neck temperature up around 650 degrees.

 

[jo191145]

The carbon in your necks has been acting as a lubricant.
Annealing has removed most of that carbon and roughened it.
Sort of like pouring water in a scalding cast iron frying pan.
You've changed the seasoning. This is normal.

One method I use to remedy this situation is apply Imperial Dry Graphite to the interior of the neck before charging.

If your using an expander ball and lube for sizing maybe skip the alcohol. An extra tumble to remove the lube should work better.
Even tumbling media has a slight lubricative property to it.
Add to that the fact it will not remove 100% of your chosen lube and it should get you closer to the tension your used to.

 

[Jeffvn]

475 degrees is not getting the necks hot enough to actually anneal them.

Here are two articles to read:

annealing #1

Annealing #2


Jeffvn