Best case mouth lube for accuracy?

[Shinbone]

I am wondering what people use for lubing the case mouth ID prior to seating the bullet for accuracy purposes?

Preface: Cases are annealed after each firing. The only cleaning operation I do to the case mouth ID prior to seating the bullet is to brush them out with a nylon brush (i.e. no tumbling, no ultrasonic cleaning, etc.), thus presumably leaving some carbon in place. Bullets are seated using an arbor press and a Wilson seating die.

For bullet seating, I started out using powder graphite on the case mouth ID brushed on dry with a bore mop. I also coated the bullet shank with the same dry powder using a small container of ceramic beads.

I then switched over to using moly powder for the case mouth and bullet shank, applied in the same way, and I think I noticed a slightly easier seating force.

One time, I got lazy and left the Imperial Sizing Wax in the mouth ID after an expanding operation, and for sure noticed an easier seating force, and also observed generally lower ES's. But, the ISW has obvious problems such as powder sticking to it, and the possibility of some powder contamination. But the lower ES's caught my attention, making me think that maybe there is a better way to lube the case mouth ID than what I had been doing.

I did a search on the subject. I see lots of threads for lubing the case mouth OD for sizing purposes, and some threads on lubing the case mouth ID to prevent bullet weld (for example: https://forum.accurateshooter.com/threads/lube-inside-case-mouth.4064505/), but I found pretty much nothing in regards to accuracy. I am interested in hearing what other people do to lube the case mouth ID for best accuracy?

 

[RustyInBend]

I use NeoLube #2 before my mandrel step, and leave that residual NeoLube in the neck and it works great for seating without a second application. My AMP Press gives me great data about seating pressure, and this methodology works great ... very consistent seating curve.

 

[bozo699]

In my opinion you’re already doing it. If you leave the carbon in the neck as I see your doing and you brush it with with a nylon brush as your doing, I always brush each case the same they should seat very smoothly and consistently which for me has resulted in better accuracy. On new brass I use dry imperial lube in ceramic beads.
Wayne

 

[One Eye Pete]

Just my two cents
If you don't anneal or clean the cases and have residual carbon in the neck that works fine.
When I anneal and/or clean the cases I use a mix of moly powder in 91% rubbing alcohol applied with a suitable size bore mop to the inside of the case necks. This works well and I have found it a lot less messy than trying to work with graphite or moly in powder form. I guess the moly powder in alcohol works similar to NeoLube but is a lot cheaper.
My experience has been that dry lubricants on the inside of the neck help with bullet seating and accuracy. When I tried wet lubes (oil or wax) they helped with seating force but for some reason detracted from accuracy.

 

[Shinbone]

What about using Lee Resizing Lubricant prior to bullet seating? It can be allowed to dry to prevent powder from sticking to it, and Lee claims that it won't degrade powder.

Resizing Lube - 1 Tube

Lee Resizing Lube eliminates stuck and dented cases, makes sizing less work. Non-sticky, non-allergenic, and can be thinned with water

leeprecision.com

 

[M-61]

Nothing. Maybe a pass with a nylon brush for a stuck piece of media.

 

[Tesoro]

I'm no BR pro by any means but if accuracy is the concern then I believe primary attention should be on having an all around even neck wall thickness than what lube you use on top of smooth carboned necks, if any.

 

[marchboom]

I'll throw in my 2 cents. (1 cent now under bidenflation)

Consistency in bullet release greatly affects ES and SD and, therefore, good accuracy SHOULD be the result. I remove the carbon from the ID of the neck because this way I have the same neck surface every time. I don't know of a way to brush the neck and have that result in the same amount of carbon residue remaining every time. So I remove all of it. I use FL sizing (without the expander) and then use a mandrel to set the ID of the neck. BTW, I mostly use moly coated bullets so I guess that could be called lube.

 

[Shinbone]

MB - do you apply any type of lube to the case mouth ID, itself, or, are you only lubing the bullet?

 

[4xforfun]

DRY case necks for me.

 

[Clancy]

You should be sizing after annealing, so:

If you’re using an expander ball, I run a naked nylon brush through the neck then run the case over another nylon brush that has a small amount of imperial on it. After sizing, I briefly swab each neck with a q tip.

If you’re not using an expander, just make two passes with the nylon brush. The carbon will do the rest for you.

 

[TheCZKid]

I'm working on solving the consistent neck tension / neck lube issue myself right now. I'm going to prep about 1000 cases to load this winter, and from the info I found, I'm going to use Neolube #2 on the necks.

My brass is all new and ultrasonic cleaned, and I noticed on my test loads I have had irregular neck tension while loading. The necks are all turned, as they have to be to make the 20 Vartarg brass, as well as annealed. I'll use a bushing on the outside to slightly size down, then finalize all the neck sizing soon on size final inside ID using a K&M mandrel.

Then apply a thin layer of Neolube #2 to the inside, and load. From what I've learned the Neolube does lowers the ES and SD and results in consistently smaller groups.

Erik Cortina says he no longer cleans his brass, says it's a waste of time, and shows no difference in accuracy. He uses the carbon left in the necks as his lube.

 

[Mastershot]

I tried the lube on the necks, I stopped doing this because my fine powder was sticking to the lube and making a mess trying to load. I just only do dry necks now.

 

[bozo699]

I'm working on solving the consistent neck tension / neck lube issue myself right now. I'm going to prep about 1000 cases to load this winter, and from the info I found, I'm going to use Neolube #2 on the necks.

My brass is all new and ultrasonic cleaned, and I noticed on my test loads I have had irregular neck tension while loading. The necks are all turned, as they have to be to make the 20 Vartarg brass, as well as annealed. I'll use a bushing on the outside to slightly size down, then finalize all the neck sizing soon on size final inside ID using a K&M mandrel.

Then apply a thin layer of Neolube #2 to the inside, and load. From what I've learned the Neolube does lowers the ES and SD and results in consistently smaller groups.

Erik Cortina says he no longer cleans his brass, says it's a waste of time, and shows no difference in accuracy. He uses the carbon left in the necks as his lube.

IMHO Erik is 100% correct
Wayne

 

[TheCZKid]

IMHO Erik is 100% correct
Wayne

In the past I've always cleaned my brass with the ultrasonic cleaner, and never used a neck lube, for years. Recently, while loading a bunch of 17 Hornet for future use, I started dipping the base of the bullets into Imperial Dry Lube, to keep from having the "weld" issue. But I know I have hundreds of round of mostly 9mm and 223 which has just bare brass to bullet contact, and wonder how they are going to shoot.

 

[RegionRat]

Food for thought.

Testing one factor at a time is something you often hear, but it can let you down as fast as making too many changes at once depending on the context.

For example, just for a moment think of the average value of neck tension as a parameter that often affects the performance of both the target and velocity stats. In theory seating force changes due to what we call neck tension affect combustion.

That combustion may have a window where it takes a change of a certain size to that average seating force before you get a change on the target or the speeds. However.... hold that thought for a moment.

When we look at things like friction, there is often an average value and then there is the dispersion around that value.

Now consider that different types of friction and lubricants exist, and in general when the topic is neck friction we would find that as the average value of seating force climbs, so does the dispersion around that average value. So, the spread in seating forces that average 35 pounds may not be the same as the spread of an average of 70 lbs with unlubricated friction.

And further, in general if we "lubricate" that seating force, we not only drop the average value but we also see a reduction in the dispersion around the average.



If we took a "lubricated" average around 35 pounds, versus an lubricated average around 70 pounds, they would both have less dispersion around their averages compared to those same averages using squeaky clean unlubricated friction. But be careful, since we may not have good performance when one of those averages is outside the happy combustion window...

So, by lowering the friction coefficient in the necks we do two things, lower the average seating force but also reduce the variation around that average. Now back to that first concept of neck tension and seating force as an independent variable.

If your experiment only lubricates, but doesn't circle back to setting the same average seating force, you can imagine what happens when the combustion isn't happy with that lowered total seating force even if it has a very tight low average. What can happen in some instances, is when the seating force average is held the same, but one is lubricated and thus lower dispersion, versus the same one "dry" and thus noisy, the lubricated one will generally produce more accuracy and precision.

By just looking at lubrication and not circling back to see if the combustion required staying in the happy spot, you can find yourself drawing the wrong conclusion. Sometimes it stays in the happy window and Bob's Your Uncle, other times it ruins performance. You don't always get away with playing one variable at a time.... YMMV

Merry Christmas and Happy New Year

 

[searcher]

The problem with any of the lubes, graphite, etc. is getting each case the same. Seems the best ways I've found are to either use no lube, or treat the actual bullet, such as with Moly or HBN, etc. Each of the two methods has its own drawbacks though. Using no lube can result in some pretty wild differences in seating pressure unless the necks are carefully turned and, as you are doing, annealing. Using coated bullets tends to require several (or more) rounds fired through the tube to get the load to settle down and obtain uniform velocities. If I were using the load for hunting, I'd use no lube for a consistent first-shot. If high-volume varmint shooting, moly is the best, hands down. For matches, I tend to lean towards moly as long as I can get in at least a half dozen sighters. In small-neck cartridges of .20 caliber and under, using moly can often result in not being able to get enough neck tension, regardless of how small you neck down - unless one crimps - and I won't do that ever. It does depend on the cartridge and use. I haven't experimented enough over a chrono with other lubes applied to the necks or bullet bases to see the effect. Also, how long one plans on storing the ammo might dictate which method I'd use. long term storage ammo would be molly coated - and definitely not bare.

 

[Shinbone]

Region Rat - My thoughts exactly. The reduced ES I was seeing with the ISW was due to reducing friction which concurrently reduced the numerical amount of the variation in friction.

 

[TheCZKid]

The problem with any of the lubes, graphite, etc. is getting each case the same. Seems the best ways I've found are to either use no lube, or treat the actual bullet, such as with Moly or HBN, etc. Each of the two methods has its own drawbacks though. Using no lube can result in some pretty wild differences in seating pressure unless the necks are carefully turned and, as you are doing, annealing. Using coated bullets tends to require several (or more) rounds fired through the tube to get the load to settle down and obtain uniform velocities. If I were using the load for hunting, I'd use no lube for a consistent first-shot. If high-volume varmint shooting, moly is the best, hands down. For matches, I tend to lean towards moly as long as I can get in at least a half dozen sighters. In small-neck cartridges of .20 caliber and under, using moly can often result in not being able to get enough neck tension, regardless of how small you neck down - unless one crimps - and I won't do that ever. It does depend on the cartridge and use. I haven't experimented enough over a chrono with other lubes applied to the necks or bullet bases to see the effect. Also, how long one plans on storing the ammo might dictate which method I'd use. long term storage ammo would be molly coated - and definitely not bare.

So, using the Neolube on 20 Vartarg cases might cause there to be not enough neck tension?

 

[searcher]

So, using the Neolube on 20 Vartarg cases might cause there to be not enough neck tension?

I haven't tried the Neolube - so can't really say. I use Moly on all my bullets in high-volume varmint shooting (mostly .223 and .22 Nosler) - but had so many issues with moly in the .20 cal necks in my A/R's, I don't use it in those. There is just so little surface area on the inside of those small necks, it seems that no matter how much tension I put on the necks, those slippery little bullets would always find a way to move a bit on the loading cycle, resulting in erratic accuracy, especially when using the smaller 32 grain bullets. Using 40 grain lead-free, with the longer bullet, was the least troublesome - but overall, I found that bare cases and bullets worked much better in the .20. (Practical). If I were shooting in a bolt gun, I'd moly those little suckers. I even moly my .17 caliber bullets in my bolt gun.