Lubing the inside of case mouths

[AtlLaw]

A thread on case lube on the Yahoo Handloading List got me thinking... 
 
While I've used Hornady One-Shot spray case lube for quite a while, I was never satisfied with the "spray into the case mouth" method of lubing that area.  So, after the outside of the care was lubed, I use a bit of Lee's Lube on a Q-Tip to lube the inside of each case mouth.
 
I lube the inside of the mouth in an attempt to lessen the friction of the expander ball being withdrawn from the case.  By doing this I hope to minimise the stretching of the case.  After all, I spend a lot of time adjusting the dies to just "bump" the shoulder of the brass!  Oh! and also because I have always heard you should lube the inside of the case mouth!   
 
Problem is, sometimes I forget to brush the inside of the mouth before I clean the cases, and sometime I forget to lube the inside of the mouth before I size the case...    Sometimes I forget both!     And I usually don't even notice my oversight until the cases are sized!     So lubing the inside of the case mouth can't only be a "YOU'LL STICK A CASE" thing!
 
But then again, I have never considered these acts as factors in contributing to the accuracy of a given round.
 
Now, since this is a new thought, I have never done one of my meaningless and statistically insignificant experiments to see if forgetting to do one or the other or both had any detrimental effect on accuracy.  But if not brushing or lubing the inside of the case mouth isn't necessary for the sizing of a case, and doesn't have any effect on the accuracy of a round, why do we do it? 

[SHOOTALL]

I'm sure this will draw fire but at one time I used the RCBS squeeze bottle lube. put a little in a dish got it on my fingers and lubed cases. When sizing if cases were sticking I would place some in one case mouth and it seemed to lube the ball for several more cases. Now I spray cases on the out side but still use the lube on the mouth. I have done this for years and never had a problem with ammo and some is now over 20 years old or maybe more.

[Hairy Chest]

A thread on case lube on the Yahoo Handloading List got me thinking... 
 
While I've used Hornady One-Shot spray case lube for quite a while, I was never satisfied with the "spray into the case mouth" method of lubing that area.  So, after the outside of the care was lubed, I use a bit of Lee's Lube on a Q-Tip to lube the inside of each case mouth.
 
I lube the inside of the mouth in an attempt to lessen the friction of the expander ball being withdrawn from the case.  By doing this I hope to minimise the stretching of the case.  After all, I spend a lot of time adjusting the dies to just "bump" the shoulder of the brass!  Oh! and also because I have always heard you should lube the inside of the case mouth!   
 
Problem is, sometimes I forget to brush the inside of the mouth before I clean the cases, and sometime I forget to lube the inside of the mouth before I size the case...    Sometimes I forget both!     And I usually don't even notice my oversight until the cases are sized!     So lubing the inside of the case mouth can't only be a "YOU'LL STICK A CASE" thing!
 
But then again, I have never considered these acts as factors in contributing to the accuracy of a given round.
 
Now, since this is a new thought, I have never done one of my meaningless and statistically insignificant experiments to see if forgetting to do one or the other or both had any detrimental effect on accuracy.  But if not brushing or lubing the inside of the case mouth isn't necessary for the sizing of a case, and doesn't have any effect on the accuracy of a round, why do we do it? 

I agree.  Why do something if not needed? I have seen many expert articles about making sure you brush the necks and lube.  The brush and lube are sitting gathering dust.  Same with primer pockets.  Just leave them alone.  If a primer doesn't seat deep enough, then clean them. 

[Larry L]

Here's a test for you. Take a fairly decent capacity case like a 3006. Prepare the case like you normally do and use a lube on the inside of the case mouth. Tumble the brass for a couple of hours to remove any lube. Measure the case OAL. Clean the die especially the stem and sizing ball. Now resize the case with no lube on the neck. Remeasure the case OAL. You'll find that the case is now several thousandths longer. Why? Because the force of dragging the sizing ball back thru the case neck has stretched the case. No, it's not a lot but if you are looking for accurate loads, it all has to be the same. If you are crimping and expect accurate loads, the OAL MUST be the same or you'll get inconsistent crimp pressure. I've seen reloads that the ammo won't go into a chamber because the datum line on the brass has been pulled out by the resizing ball to the point the shoulder area is the wrong size/angle. Most any lube will work on a case neck including cheap motor oil. Why not make it a practice to keep a small bottle of oil on the bench with a neck lube brush and lube as you go? It's not a difficult job.

[geezerbiker]

I've also found the expander ball will remove more brass if I forget to lube the inside of case necks.  This is obvious when I take the die apart to clean it afterward as there will be more brass build up on the ball.

Tony

[Old Syko]

Like Larry L I've seen brass distorted to the point it would not chamber due to being sized with a dry inside neck.  In order to avoid this I keep a ball of RCBS lube in the corner of my lube pad and run the neck down the edge of the ball while dragging the case toward me.  This keeps the lube inside the neck and avoids too much lube buildup on the outside that will cause wrinkled shoulders.  BTW I would rather have wrinkled shoulders on cases that will chamber and fire than cases that won't chamber at all.  The spray lubes have been relegated to straight wall cases only.  Just not enough lubricity for bottleneck cases.  I've found this to have a big effect on accuracy.  Improper lube causes too many different distortions.

[D Fischer]

I'm sure I've sized cases without lubing the mouth but can't remember when. Pretty much have always done it. The best lube I ever used was STP applied with a Q-tip. I've used RCBS lube, Dillion lube and now just spray with one shot. I know my case's stretch when sizing but the thing that minimized it most was the STP. Just want to make sure you get that stuff out, I used a Q-tip and lighter fluid to clean it out. Now the best way to stop it seem's to be a collet sizing die. I got one for my 243 and it doesn't stretch case's.

[mechanic]

I lube and size before I tumble.  Thus, I just spray inside and out, then the cleaner cleans it all up.
 
Ben

[Dee]

I lube and size before I tumble.  Thus, I just spray inside and out, then the cleaner cleans it all up.
 
Ben

I do this also, but when I got my dies, I took the expander ball out, and put a high polish on it with a buffing wheel, and jeweler's rouge. Never concerned myself with it after that.

[roper]

You can always buy the Redding type S bushing die that will include retainer so you don't have to use standard type expander.

[Dee]

I have been using the same 3030 dies (RCBS) for over 40 years now. I think I'll keep usin these.

[cybin]

I don't lube inside straight wall pistol brass, but if I don't lube the inside of my 7MM Mag, or .223 I will be tearing off the rim area where the shell holder holds the brass. I use the Lee lube as it doesn't contaminate the powder, and I only lightly try to clean it out of the neck. I put it on by only rolling a small bead around the neck edge--I put it on my fingers and just scrape it into the neck.
 
cybin

[Graybeard]

For far too many years to even remember when I started I've used nothing but the RCBS spray lube in the pump bottles. When lubing I always spray from above as well as level with the cases to get some in the case necks. It's rare that isn't enough but if I feel cases in a lot that seem to need it I'll put a little of it on a Q-Tip and run it around in the mouth of every fifth or so case and that seems enough.

Being basically lazy I do no more than I really have to. I'm guessing I've been doing it this way for something over 20 years maybe a good deal longer.

On straight wall cases I use carbide dies only and don't put any lube anywhere on them.

[Land_Owner]

This is just "Prototype" stuff that works for me:

Onto a 2" x 4" x 6" block, screw a thin, stiff, metal plate into which is threaded a bronze or nylon cleaning brush of the case caliber.  Drill a hole in the metal plate nearly the diameter of the brush threads.  Poke brush threads through the hole in the metal plate and secure with a washer and nut.  Screw metal plate to 2x4.  You might drill a slight hole in the 2x4 to receive the brush threads and the nut.  Isn't really needed though.

I use my hands to lube the outsides of several hundreds of cases at one time (say 500 x 223).   Prior to case sizing wipe a smidgeon of RCBS Case Lube over the brush in the 2x4.  Then jamb the neck of a case over the brush to lube the inside of the case mouth.  Replenish when it appears to be dry.  Every 2nd, 3rd or 4th case neck gets lubed.  Depends on the stiffness of the operation.  Residual lube on the expander ball will in general allow 2 and sometimes 3 cases to be sized before becoming too dry.


On another Note:
It occurs to me that with any spray type lubricant that a portion, say 30% (you chose), is wasted as it is not applied exactly where it is wanted.  Over spray, too much spray, and parts not intended being lubed generate the waste.