Test-Effect of Brushing Necks vs Graphite vs Both on ES

[Bingoc]

I recently shared with fellow F Class friend using Mica to dry lube case necks after cleaning necks with bronze brush. He used small container with #9 shot. He does have a K & M strain gauge to test this. His before readings was 40-50 and then with Mica down to 10-20. He did not chronograph but it was neat to hear of the 66% reduction. He will shoot a match coming up. This is for his Lupua 6.5 Creedmoor brass.

Please keep us informed. I am not aware of how the burned graphite from the neck could affect the bore, but that is a good question. Are there any material engineers or chemical engineers that could provide an opinion?
Thanks,

 

[Chase723]

This was a good test.
I want to make a point about testing. For example, I have used colloidal graphite for years inside case necks testing for accuracy. It will win the "reloading bench match" every time, it has by far the best seating force reduction and consistency. It has never shot best on target in every rifle I have ever tried it in. Pay attention to how things play out at the bench and on the chrony, but always listen to the target.

Alex, I'm totally with you. The bullets and targets never lie. Reading what you've posted on here over the years has been extremely helpful to me personally. Frankly, a lot of what I do comes directly from stuff you've written. Not to get soft or anything but I want you to know that I appreciate you sharing your experience and knowledge.

The next thing I think I'm going to test is sorting brass by velocity. Meaning I'm going to load up 20 rounds, shoot them over the chrony, and then cull the cases that aren't within 5fps of each other. Then re-prep, load, and shoot the keepers over the chrony again and see if just doing that will result in lower ES/SD. Have you tried that?

 

[Wedgy]

The next thing I think I'm going to test is sorting brass by velocity. Meaning I'm going to load up 20 rounds, shoot them over the chrony, and then cull the cases that aren't within 5fps of each other. Then re-prep, load, and shoot the keepers over the chrony again and see if just doing that will result in lower ES/SD. Have you tried that?

that's a good idea. I think the widely regarded "most accurate" way to cull cases is by internal volume. Now if you recorded all their velocities then sorted them by weight and volume to see the differences those factors have, that could give some insight.

 

[Alex Wheeler]

Alex, I'm totally with you. The bullets and targets never lie. Reading what you've posted on here over the years has been extremely helpful to me personally. Frankly, a lot of what I do comes directly from stuff you've written. Not to get soft or anything but I want you to know that I appreciate you sharing your experience and knowledge.

The next thing I think I'm going to test is sorting brass by velocity. Meaning I'm going to load up 20 rounds, shoot them over the chrony, and then cull the cases that aren't within 5fps of each other. Then re-prep, load, and shoot the keepers over the chrony again and see if just doing that will result in lower ES/SD. Have you tried that?

Color the bullet and shoot them at long range. Or number them somehow to see if the vertical correlates to the chrony...

 

[RD57]

In 2010 I tried the sorting of cases by velocity experiment and I found it to be a waste of time, bullets and powder. In my simple experiment I used weight sorted Winchester 243 brass from the same lot. It was pretty awesome getting 35 out of 50 pieces of brass within .3 grains of each other. From that group I used 20 pieces of brass that was within .2 grains of each other. After fireforming the brass and full length sizing with a .002 bump on the shoulder I went to work with my experiment. Long story short, I found that proper neck tension and carefully weighed powder charges (to the kernel) the most important part of the low ES/SD equation. Proper neck tension is a loaded topic as it covers many variables. For my experiment optimum results depended upon annealing every other load, lightly brushing/cleaning the interior case neck and determining what degree of sizing on the neck my rifle/bullet/powder combo wanted. I've settled on annealing after 3 firings, lightly brushing interior of neck (1 pass with bore brush) before resizing on my hunting loads. I routinely get single digit SDs with my 270 Winchester and ESs from 14 to 11 fps. The cases used in my 270 are weight sorted to within .7 grains of each other for a total spread of 1.4 grains.

Looking through my notes I found that bullet seating depth or more specifically the distance the ogive was from the lands played an important role in low ES as well. With this rifle and bullet/powder combo by moving the bullet .020" either way affected accuracy and ES. In my experience I don't think you will see a measurable improvement with ESs or accuracy by varying neck tension until after you have a proven load combination that performs well in that rifle.

 

[Wedgy]

The cases used in my 270 are weight sorted to within .7 grains of each other for a total spread of 1.4 grains.

It would seem that if the outside dimensions and the weight are the that the volume should be very close.
What do you do for cleaning, tumbling, wet tumbling ?

 

[RD57]

I use a vibratory Thumbler tumbler with corn cob blasting media with some Flitz case polish. I clean just enough to keep the tarnish off the brass and preserve my resizing dies. I tried wet with stainless pins which I still use with range recovered pistol brass and once fired LC brass and sonic cleaning which is used only for cases used with black powder now. I found the light powder residue from the corn cob/flitz cleaning actually helps with bullet seating and low ES/SDs.

 

[Wedgy]

Same here, squeaky clean wasn't what worked best for me.

 

[jdmecomber]

Thought I'd do a little test this morning and share the results with you guys. After watching the video Shawn Carlock posted about reducing ES and the video by Annealing Made Perfect where they brush out the inside of a case neck and then measure seating force, I wanted to see what effect both brushing out necks and graphite had on ES in one of my rifles. I normally don't do either of those things in my reloading operation.

So, I took my 6.5 Creed and loaded up a total of 40 rounds. 10 control rounds (C) that are loaded the same as usual 10 where I brushed the necks with a single pass of a nylon brush in and out (B), 10 where I applied graphite to bullet base (via the Imperial graphite dry lube little ceramic bead applicator deal) prior to seating (G), and 10 where I both brushed the necks and then applied graphite to the bullet prior to seating (Bg). I then shot them over my Magnetospeed round Robin Style (I.E. 10 groups of 4 comprised of 1 of each CBGBg), at 30-45 second intervals between each round, so that the effects of barrel heat would be similar across all groups. The results were somewhat surprising.

ES was lowest in the brushed only group and went in the following order. B<C<G<Bg.

When I throw out the highest and lowest velocity shot from each group the ES' were as follows:
B:20
C:24
G:28
Bg:53

It was also interesting to see how a 40 round group printed. The rifle will pretty routinely shoot groups in the .2s and .3s at 500. I shot at 525. The group ended up being just over 1 MOA. I suspect this is due to multiple things, zero/POI shift due to heat being one of them, especially since the 1st 8 rounds impacted in essentially the same spot. That said it was a pretty educational morning. I don't think I'll be using graphite.

I'm going to load up 10-15 more where I brush the neck out and see if anything changes from an accuracy standpoint. If they shoot the same then that was a pretty easy way to improve the long range potential of a load.

Good test.
I think cleaned brass vs brushed would even be better.

 

[highdrum]

I salt bath anneal, and the 950° cooks all carbon off neck down to bare brass. I then dip the bullet into graphite prior to seating, if not I can tell I'm applying a noticeable more force to the ram while seating. I have to lube the neck by some means.

 

[Korhil78]

I have been thinking about loading up rounds and every now and then when you are seating bullets, you notice that some bullets take more force to seat than the majority of the others. Mark those and if the velocity on them is out of whack, just use them as foulers.

I think the neck tension will affect the pressure and velocity.

 

[Greasegun]

Good write up. I enjoy seeing real data. Just a suggestion, but I think SD tells you more than ES because it uses every data point, where ES throws out all but the hi/lo points.

I see SDs around 5 with un-annealed lapua brass in my 6.5 cm, using H4350. Using a chargemaster lite. I just brush the necks with a nylon brush, which leaves the carbon in there for the most part. I have never had good results using graphite either. Maybe I missed it but what brass are you using? Have you experimented with primers in this manner?

 

[Chase723]

I'm using Alpha brass. Based on this I'm going to start brushing my necks too. To some extent I think SDs are important, however ES encompasses the SD. I agree that it's a measure of low to high but my expectation is that I have a random distribution therein and thus the lower the ES, the lower the SD. It's possible to have a group with an ES and SD the exact same if your rounds only managed to shoot 2 velocities...but that is highly unlikely...really I just wish that I had a range where I could shoot 1000 yards regularly...I'm working on that. Then I'll just do load development at 1000 and let the target do the work for me.

 

[Korhil78]

Gotta be careful with doing load work up at 1000. Wind will screw your data. But I'm sure you realize that.