School me on Bullet seating force tools

[mikecr]

Except this does not pass tests jlow. Things are happening way faster than you think.
Friction means little to nothing for actual bullet release, pressures, and muzzle velocities.
Test this with most any friction reducer/increaser other than moly, and you will see this. Moly won't work for the test because MV is reduced by moly due it's latent heat of vaporization.

Keep in mind, ANY neck expansion clear of bullet dimension, to near atomic scale, means complete release of that bullet.
And, it takes very low pressures(tiny percentage of peak pressure) to cause this.
Still, it affects peak pressure & timing, because everything about both affect each other.

 

[Alex Wheeler]

So... question for you guys that use these things more. When I use a regular press with threaded dies, its set up to run to a stop. When it stops, the seating depth is what it is... consistently, pretty much every time, +/- 0.001". Yeah, if I lean on the handle I can fudge that either way a bit, but with normal sane operation, its remarkably consistent.

When I use a hand die in an arbor press... it suddenly becomes *very* dependent on the seating force. If the die is set for seating depth with cases that have relatively light neck tension, and I have one case that has heavier neck tension... that one is going to be longer. Pretty much every time. And vice versa... if I have it set at a heavier neck tension and come across a case with lighter neck tension, that bullet is going to be seated a couple thou deeper - every time. The die is going to full 'stop', just like on the threaded press - or at least it feels like it - but the result is very different.

It's very frustrating... in theory the arbor press and hand dies should be giving more consistent seating, but in actual practice I end up chasing the seating depth all over and getting generally irritated with it. I find myself using the seating force tool more as an indicator of whether or not the seating depth is consistent, than any special neck-tension magic. Or I can load the same rounds on my Co-Ax or 550 and have more consistent seating depth, with less headaches.

What's going on here?

What you have going on is a difference in seating stems. Study them both. The one in your hand die is letting the bullet slide into the stem to easily. It is most likely contacting higher up the bullet and has a smaller contact area. Higher seating force and the bullet forces into the stem and you have a longer oal. Nothing to do with the press. Hope you get it fixed, I think you will find better lengths with your hand dies.

 

[jlow]

Except this does not pass tests jlow. Things are happening way faster than you think.
Friction means little to nothing for actual bullet release, pressures, and muzzle velocities.
Test this with most any friction reducer/increaser other than moly, and you will see this. Moly won't work for the test because MV is reduced by moly due it's latent heat of vaporization.

Keep in mind, ANY neck expansion clear of bullet dimension, to near atomic scale, means complete release of that bullet.
And, it takes very low pressures(tiny percentage of peak pressure) to cause this.
Still, it affects peak pressure & timing, because everything about both affect each other.

You are of course correct that it take a tiny percentage of peak pressure (we are after all talking about 50,000-60,000 psi, so that is obvious) to expand the neck, BUT, it takes even less pressure to start to move the bullet....

Just ask yourself this simple question - Why would the bullet sit still while the same pressure pushing it forward is expanding the neck??????

 

[JohnKielly]

... or consider what a primer does when you forget to put powder in a case.

 

[Alex Wheeler]

... or consider what a primer does when you forget to put powder in a case.

Prime example of what happens if the bullet slides out of the neck. The neck does not expand.

 

[Alex Wheeler]

All any of us should care about is what effect seating force variation has on the target. Do your own testing, and dont listen to any of us if you really want to know and become a better shooter/loader.

 

[gilmillan1]

Seating force has little to do with accuracy.
Bullets and brass give different force ratings as they are seated depending on hardness.
Bullets are released by neck expansion, not interference force/neck tension, as most believe. As soon as the primer ignites, the neck tension is lost, just as it is if you re-seat a bullet or pull it.

I don't see any advantage knowing how much force is needed to seat a bullet if for only deducing whether the brass hardness is uniform. A commercial hardness tester could tell you that, if you wish.

Cheers.

Totally disagree. Neck tension has a lot to do with accuracy. If one round has significantly more neck tension, it will shoot different than the rest.

 

[Alex Wheeler]

Totally disagree. Neck tension has a lot to do with accuracy. If one round has significantly more neck tension, it will shoot different than the rest.

Your 100% right. Problem is, seating force does not correlate with neck tension.

 

[Joe R]

Your 100% right. Problem is, seating force does not correlate with neck tension.

Alex,
With all due respect, I disagree.

Although seating pressure does not measure neck tension directly it simply has to correlate to neck tension. It is a logical but indirect way to measure neck tension. IMO jlow nailed it. Your argument is a lot like someone saying that blood pressure does not correlate to arterial blockage. Tell that to a doctor or even a nurse and they will smile and walk away.

Kindest regards,

Joe

 

[tuttlefarm]

Your 100% right. Problem is, seating force does not correlate with neck tension.

Alex, I believe you are only half right, neck tension or friction......... some say the glass is half full, some say it is half empty... Lets see if some people can follow this, a bullet traveling down a barrel has friction, if you crimp a bullet in the case you have tension...... less friction equals less pressure, less tension usually equals less pressure.... but Alex you are correct........ if you want to shoot very good, wear out some barrels and do systematic testing and see what works for you.

 

[Joe R]

I have read some posts on this site and the K&M press with force gauge seems to have favorable reviews. Are there any other seating force measurement tools or models that are better than the K&M?


I read of a press that used a hydraulic gauge rather than the standard force gauge. Would a hydraulic system be better or just a different way to get the same results?

Thanks,
Trevor

Hengehold,
Once you pick your tool (I would take Erik Cortina's advice without a second thought) the next step is how to consistently control neck tension. That's a real tough nut to crack and it took me about a year to figure that out. Here's my posting from another thread:

I know that everyone likes to control neck tension with bushings but to me that doesn't seem like a very good way. From my way of thinking bushings transfer any variance in neck thickness to the inside of the neck where they have a direct impact on neck tension. That is not a good thing, because no matter how careful you are turning necks there will be variances, and those variances will impact neck tension.

I believe that the outside of the neck has minimal importance. The only important thing is how thick the necks are because that has an influence on spring-back. IMO the part of the neck everyone should be focusing on is the inside of the neck, or more appropriately inside diameter. The inside diameter is what influences neck tension, if one can transfer neck wall variances to the outside of the case it is that much better.

So the question is how do we control neck tension from the inside of the neck? What if instead of honing die necks (an irreversible and often problematic process because dies are hardened, not to mention that you have to be twice as accurate with a die then with a mandrel, an impossible task) we were to use a mandrel to expand the necks to provide the desired neck tension? What would a mandrel do?

Well, ... a mandrel would control the inside diameter of a case neck much more precisely than any bushing ever can. It could also transfer neck thickness variances to the outside of the neck where it doesn't interfere with neck tension and bullet release. That's good isn't it?

I have been using mandrels for thousands of cases. The problem is that just when I have a mandrel that gives ideal neck tension (down to .0001 precision) it starts to wear, and after a 1,000 cases it is done. Making another mandrel to .0001 precision is very difficult/not possible for most machine shops and grinding shops. So I set out to look for a solution.

Pin gages are small tubes 2" long and can be bought for a few dollars and they are available in dimensions as exact as .0001 (+/- .00002). They generally have a 60 to 62 Rockwell hardness, like tool steel. They are ideal for this purpose, all you have to do is bevel the tip.

Well, ... to make a long story short Kenny Porter (Porter Precision Products in Lake Jackson, Texas) made this die for me last week. The collet he used is made for lathes so it holds mandrels perfectly straight. This mandrel die makes all other mandrel die I have seen or bought look primitive.

Regards

Joe

 

[dkhunt14]

I use the k&m, but haven't played with the hydro one from John. As far as whether I think it matters..... 2010 I thought "yes", 2011 "no", 2012 "yes" etc etc. I know I've set what were supposed to be "match" sets aside and made replacements, due to the seating force being a little erratic.... I fired those "culls" on a Friday night before the match and sure would've loved to have traded them for the targets I shot in the match lol.

Tom

It could have been condition differences. Late evenings at Williamsport give way better conditions then we see the next day. Those vertical fliers seem to really almost disappear in the evening. Sometimes you get away with it and sometimes you dont. LOL That is why I won't test in the evenings. Because it is never like a match. matt

 

[rardoin]

What you have going on is a difference in seating stems. Study them both. The one in your hand die is letting the bullet slide into the stem to easily. It is most likely contacting higher up the bullet and has a smaller contact area. Higher seating force and the bullet forces into the stem and you have a longer oal. Nothing to do with the press. Hope you get it fixed, I think you will find better lengths with your hand dies.

In addition, if there is a difference in the seating force, you can expect more elastic deformation of the neck/shoulder junction during seating a 'high force' round compared to one requiring less force. The resulting rebound (or springback if you prefer) of the brass will result in a longer CBTO of those rounds. I use an arbor press and Wilson dies and have noticed this also. This occurrence was reduced dramatically when I changed annealing methods. When I do get a 'hard' seat I use that round as a fouler.

 

[Alex Wheeler]

Alex, I believe you are only half right, neck tension or friction......... some say the glass is half full, some say it is half empty... Lets see if some people can follow this, a bullet traveling down a barrel has friction, if you crimp a bullet in the case you have tension...... less friction equals less pressure, less tension usually equals less pressure.... but Alex you are correct........ if you want to shoot very good, wear out some barrels and do systematic testing and see what works for you.

I tested all this stuff years ago. Its one of the easiest tests a shooter can do, its all bench work. Grab some cases and prep them
1. polish inside of the neck with steel wool
2. polish with nylon brush
3. polish with nylon brush dipped in graphite
4. un touched neck
5. untouched neck out of the annealer

Seat bullets in those cases and you will see a huge difference in pressure. Use the same bushing. Next take 3 cases and prep like 2. and use 3 different sized bushings. You will probably have a hard time deciding which ones used which bushing.

In my experience seating force is 90% friction 10% tension.

Then take some ammo to the 1k line, your worst and best groups sorted off the seater. Then you will know. If your findings are different then mine, I will have to revisit my testing.

Even with what I have found in real world testing, I still pay attention to seating force and will use odd ones as sighters. Just because. But I stoppped sorting in batches of 2lb. es like I used to.

 

[dmoran]

IME, all the theories above are "right but wrong" and all irrelevant in the end.

- One may use 003 tension and brush the necks. Another may also use 003-tension, but steel wool.
- One may use bushings to set the tension, but another uses expansion.
- Even in the same caliber, the indifference in bullet shapes, weights, and diameters, let alone different calibers.
- One may not have a rifle or setup accurate enough to shoot and see much for differences, while another does.
- Ones who only need 300yds of accuracy verses the ones who need 600yds, or again ones needing 1000yds.
- Indifference to disciplines, where in one discipline a load&rifle may be capable of winning repeatably and be the cats meow, but the same load&rifle in another discipline be a mid-pack finisher and a turd.

Basically to many individual indifference's to make any one theory right or wrong....
If one wants to truly know what will work best for them, they need to test to find that out for there own individual and unique circumstances. And then be aware what is found to be righteous and works best for themselves may very well end up being opposite of someone else's circumstances and results.

My own 2-Cents
Donovan

 

[MagnumManiac]

Totally disagree. Neck tension has a lot to do with accuracy. If one round has significantly more neck tension, it will shoot different than the rest.

That's not what is being discussed.
Neck tension directly relates to start pressure, as does, more significantly, the seating depth of said projectile.
Seating force can change by many factors.
Seat a bullet in a primed case, measure the neck, fire it and remeasure the neck with a .0001" accurate micrometer. I will guarantee that the neck has expanded from the pressure generated by the primer alone.

Cheers.

 

[jlow]

Given it a lot of thought, what I think what actually happens is the neck cannot expand when the bullet is sitting in it because the pressure cannot push against the neck since the bullet is sitting there. Now as the pressure starts to push the bullet and move it forward, the neck in that area is exposed and the pressure now expands the neck in that area. Push, expose, expand, push, expose, expand… So in actuality, bullet moves before neck expands.

This is why “neck tension” plays a role in barrel time and precision.

 

[DJB]

I learned a long time ago that if you have a question if an extra step works or not, I go the extra step. That way I will not be shooting and wondering if it matters or not. Just another part of the puzzle to extreme accuracy. Doug

 

[fguffey]

I prefer 'bullet hold', when it comes to bullet hold I want all the bullet hold I can get. I would use tensions if someone would figure a way to measure tensions. I have tension gages' problem, all of my tension gages measure in pounds and there is no conversion when going from tensions to pounds.

And then there is R. Lee in his book on modern reloading he talked about pressure and time. two factors. He was talking about bullet crimp and bullet release. Anyhow, I want the neck of the case to release the bullet, I do not want the neck wedged between the chamber and bullet.

F. Guffey

 

[rgmeddn]

Hello guys. New to the forum. I was attracted to this thread because I am at exactly this point in my knowledge base, thinking about whether to incorporate bullet seating force equipment in my handloading. I was thinking that maybe there is more to be learned here about what the implications of variability in seating force - especially when excessively high - means. It might be useful if somebody would rig up a way to measure EXTRACTION force to see if it correlates with insertion force. Plus the bullets could be looked at for scoring, or at least compared to bullets of lower insertion force. Also, the case neck IDs can be compared, and another seating could be tested to see if it is the case. Seems like an opportunity for some science.
(Or maybe I should just shut up and keep reading)