It's finely ground Mica.

Mica is a mineral and really does a nice job lubricating the neck reducing friction in the sizing die specifically the sizing button. I used it for years with success and since it's inert it poses no threat to powder or primers.

 

I've been using mica for a number of years now. It works just fine & IMHO is better than graphite, but it can be almost as messy. My mica set came from Midway which has a reservoir & a series of brushes to run the necks over. A bit "cheesy" but works fine. Depending on what I'm doing/loading I still prefer to lube the necks inside with regular case lube using a bristle brush run across a lube pad every 5 rounds or so. Then I vibrate tumble to remove any traces of lube before loading. Never had a problem doing this & no none of the necks ever get deformed. I polish all my sizing die buttons per the instructions in Sinclair's Precision reloading manual which I think helps. Of course I'm talking about regular sizing dies.

FWIW

 

Thanks guys! Nothing to lose by trying the dry lube. I pulled a sizing ball off a set of .223 RCBS dies a year ago because I was not getting sufficient lube inside the case neck. Dry lube might be helpful and quicker than what I am doing now.

 

Thanks guys! Nothing to lose by trying the dry lube. I pulled a sizing ball off a set of .223 RCBS dies a year ago because I was not getting sufficient lube inside the case neck. Dry lube might be helpful and quicker than what I am doing now.

Right on, krorie. Its important to lubricate the inside of case necks before sizing and a dry lube like powdered mica or graphite is best. Applying regular sticky case lube to the inside of necks will leave a residue that normal tumbling media can't thoroughly remove. Then, when its time to charge the case with gunpowder, some of the granules will stick to the inside of the necks, causing you to stop and clean with a brush or q-tip. - CW

 

You know, I was thinking about this thread and just as a precaution I'd like to throw out a few thoughts.

Many of us lube the inside of the case neck to avoid chatter during neck sizing and also to minimize case neck stretch and it makes sense.

The principal behind firing a bullet is chamber pressure. As the powder ignites, the brass case expands sealing the chamber. Once the chamber pressure is sufficient, the bullet begins to move in the direction of least resistance, down the barrel. The further the bullet travels down the barrel the volume behind the bullet increases and the chamber pressure drops off dramatically, all in milliseconds.

By lubricating the inside of the case neck, the bullet begins to move sooner and at a lower pressure than calculated. Lower pressure affects the burn rate of the powder under pressure, reduced muzzle velocity, accuracy, and so on. Have I done a design of experiments to test just how how much various lubricants have on the firing of a cartridge? No, I haven't but it could be done with strain gauges and a chronograph under controlled conditions.

Just something to think about guys....

 

If you use RCBS or Lyman dies just buy the carbide neck expander button upgrade (270 works for 6.8 dies) and never need to lube and later clean the inside of case necks again with anything. If you use a progressive it's the only way to go.

I haven't lubricated case necks in .223, 30-06, .308, 270 or 6.8 in over a year since making the switch with no ill effects on the brass.

 

I didn't know they made the carbide neck expander button for rifle rounds. It sounds like an option I will pursue.