Seating force

[Boozer]

Had a very interesting thing happen to me as I was doing a load work up the other day. I had a handload that I had worked up, and had gotten some pretty small groups out of it thus far (best was .44 moa). but I was not getting good ES/SD. SD was in the 9-15 range, and ES was in the 30's. I just so happened to run out of cleaned prepped cases, and bullets all at the same time. So I had to reprocess all my brass, and before I resized the cases (this will be their 3rd firing) I clean with SS tumbling pins, and I annealed them all on my home brewed annealing machine. (this is change #1). I had been planning to try out HBN, so the bullets all were tumbled and the bore was swabbed with the rubbing alcohol/HBN mix (change #2).

I got all the cases charged for my load work-up, and was going to seat the first 5 as break-in/foulers for the HBN swabbed bore. The first bullet took a TREMENDOUS amount of force to seat, much more than any I've ever seen. When I actually got it seated, I decided to pull it, because I was a little worried about actually shooting the thing! Again, it took a tremendous amount of force to pull the bullet too. A second bullet in the 2nd case went much the same way. This is much different than anything I had read about HBN coated bullets, as folk say it usually say that it decreases seating force!

Another thing I wanted to try out is applying a thin film of imperial size wax on the inside of the case necks. (change #3) I had heard it really helps reduce ES/SD. So after the first 2, I starting lubing the inside of the necks, and it helped. The rest seated with what I would call a "normal" amount of force.

Main question, has anyone else ever experienced something like this when switching to annealed brass, or HBN? I know that SS pin tumbling makes cases borderline too clean, and can cause sticky case necks, but I have always cleaned with SS pins, and didn't experience this before.

The good news is that between the 3 things I changed, at least one of them worked! My SD was nearly non-existent, and my ES was 13. I was shooting 4 shot groups, and at the center of my node, out of 4 shots I had 3 at the exact same velocity, and #4 was 13fps high, so maybe I messed up the charge on that one).


I know, I know....I broke a cardinal rule of reloading. I changed more than 1 thing at a time

Accurized Rem 700 in 30-06
Bartlien 5R 1:10
3 times fired Rem brass, fully prepped and weight sorted, annealed
CCI BR2's
57.1 grains H4350
Berger 185gr classic hunters (HBN coated)

 

[dok7mm]

I have experienced the same problem with new AND annealed cases. I don't use the steel pins because I like the lubricity of a sheen of carbon in the necks. I also use the Imperial Dry Lube instead of die wax, as I get more consistent bullet release. Also brush case necks with nylon bore brush on a drill to clean after tumbling and/or annealing prior to using dry lube.

I use HBN on all my rifles, but after having your experience, I changed neck tension from .002 to .001 by changing bushings. I'm running SD of around 3-7 fps and ED of 10-15 across the board on custom rigs. The HBN works very well for consistent numbers, but sure causes sticky seating in new or pin cleaned brass. JMO

 

[Mikecr]

Seating force is not directly representing of tension, and does not directly mean anything towards MV, SD, or ES. All you did was increase seating FRICTION (not tension).

If someone invented the perfect seating lube, they would be selling you little bottles of carbon. Yet, you chose to remove it with SS pins...

 

[Korhil78]

Mike...do you use a tumbler with media to clean your brass and just brush out the case necks a bit before resizing and loading?

 

[Boozer]

I have experienced the same problem with new AND annealed cases. I don't use the steel pins because I like the lubricity of a sheen of carbon in the necks. I also use the Imperial Dry Lube instead of die wax, as I get more consistent bullet release. Also brush case necks with nylon bore brush on a drill to clean after tumbling and/or annealing prior to using dry lube.

I use HBN on all my rifles, but after having your experience, I changed neck tension from .002 to .001 by changing bushings. I'm running SD of around 3-7 fps and ED of 10-15 across the board on custom rigs. The HBN works very well for consistent numbers, but sure causes sticky seating in new or pin cleaned brass. JMO

Good to hear that I'm not completely crazy, sounds like you've experienced the same thing. I don't disagree that using the SS pin cleaning is going the opposite direction as far as consistent release is concerned, but I feel the benefits outweigh the drawbacks. I don't currently run bushing dies so changing neck tension isn't quite that easy. My Redding set is consistently .002.

 

[Boozer]

Seating force is not directly representing of tension, and does not directly mean anything towards MV, SD, or ES. All you did was increase seating FRICTION (not tension).

If someone invented the perfect seating lube, they would be selling you little bottles of carbon. Yet, you chose to remove it with SS pins...

I agree that there is much more to consistent bullet release than just neck tension. I think my little unexpected experiment proves that. That first bullet had .002 neck tension just like any other that came off my press, yet it took significantly more force to seat and remove the bullet.

I will disagree with you in that seating force or even better, pulling force, DOES directly affect MV, ES, and SD. That is the force that the ignition of powder has to overcome to get the bullet moving out of the case mouth. I think we're starting to split hairs when we differentiate between seating force and seating friction, assuming relatively consistent neck tension

 

[Gene]

My concern is that heavy seating will run up pressures. Lubricating inside of necks will lead to inconsistent bullet release. Running them thru a nylon brush is sufficient. You don't say what dies you are using. Bushing dies will allow you to control seating force.

 

[Mikecr]

Boozer, you hold a serious misconception about bullet release.
The bullet is not released through overcoming of friction. It's released with neck expansion, and even a trillionth of an inch neck expansion has totally released the bullet.

Neck tension is neck brass springing back against bullet bearing (grip). The greater the spring back against a given bullet area, the higher your tension. Lube in the neck does nothing to change this fact, it only changes seating force. The grip still has to be overcome for release, just the same, else your gun would explode.
Luckily, neck spring back is limited (~1thou), no matter how excessive you size.

When you took necks to squeaky clean, and annealed them, you increased seating force(friction).
The annealing also reduced neck tension(reduced spring back), which reduced tension variance, but changed your MV.

There is absolutely no benefit, only bad, in taking case internals to squeaky clean.

 

[Boozer]

Boozer, you hold a serious misconception about bullet release.
The bullet is not released through overcoming of friction. It's released with neck expansion, and even a trillionth of an inch neck expansion has totally released the bullet.

Neck tension is neck brass springing back against bullet bearing (grip). The greater the spring back against a given bullet area, the higher your tension. Lube in the neck does nothing to change this fact, it only changes seating force. The grip still has to be overcome for release, just the same, else your gun would explode.
Luckily, neck spring back is limited (~1thou), no matter how excessive you size.

When you took necks to squeaky clean, and annealed them, you increased seating force(friction).
The annealing also reduced neck tension(reduced spring back), which reduced tension variance, but changed your MV.

There is absolutely no benefit, only bad, in taking case internals to squeaky clean.

Mike-

I smell what you're stepping in... But you are correct, that was not my understanding of how bullet release works. It seems you and I have 2 different schools of thought. I would not say that I am set in my ways, now hearing your comments I do see the merit in that theory. ( I am assuming that we are talking about internal ballistic theory, and not internal ballistic fact!?!). If there is any scholarly articles on the subject I would love to read more on the topic of what is happening inside the case during this crucial 1 millionth of a second.

I will say this. As the charge goes off, it would seem to me that with a bullet held under light frictional force, be it due to lube or carbon or otherwise, would require less psi to start moving out of the case, than the psi required to expand the case mouth (even that 1 trillionth of an inch). So I would theorize that frictional force does matter, even if it may be for a millionth of a second until the case mouth expands enough).

After all, we cannot disregard the fact that something I did worked! (although further testing will be required to figure out if it was just one of them or a combination of 2'or more). It is not often that people cut their ES/SD more than in half!

 

[Barrelnut]

Just tagging in. Boozer, hopefully you can figure which of the changes resulted in the incredible reduction in ES. You have ne researching HBN now.

 

[Mikecr]

Annealing lowered your ES. That's your answer there.

Get yourself a good chronograph and change one thing at a time. Consider things objectively and I think you'll gain in perspectives here.
If that one thing you change is seating force (as measured), without changing tension (as I described), you will not see MV change. Then change tension, without changing seating force, and you will see MV change.
This isn't theory for me, I've done the testing with accurate measure, and fully understand it.

 

[Boozer]

Just tagging in. Boozer, hopefully you can figure which of the changes resulted in the incredible reduction in ES. You have ne researching HBN now.

Barrelnut-

Whenever I research something I tend to read everything I can find, take everything with a grain of salt, and then assume that if 75% of folks are saying the same thing, that it will generally be true. Most (including David tubb) will tell you that it has similar benefits to WS2 or Moly, but without the drawbacks of hard cleaning or being messy. In general, no cold bore shot, better ES/SD, minimal fouling, longer barrel life. It's basically pixie dust. Still too soon to call on most of these for me, but I will suspect it had something to do with the ESSD reduction. Any more questions let me know, but I'm sure there are many more on here who have used it more than me.

Though I have enjoyed how this thread has evolved, We have drifted from the origina topic of the post. I would like to hear from folks who may have experienced the same heavy seating issue that I did.

 

[CliffM]

I have on occasion when cleaning with ss media had the case mouths get rolled in slightly, just enough to make them a little hard starting. Now I give a light chamfer to every case after cleaning.

Cliff