JFrank
Member
When in doubt ? Brush it out….
I tumble to remove most of the carbon on the outside. Thumbs get tired doing it by hand.Is there a reason to vibrate in walnut once fired? Are you jacking the out case onto the ground or is the carbon so thick it requires management?
It would be interesting to run a test of lubed vs not lubed and see what it does to es & sd
Old school here, don’t want squeaky clean necks, or lube left in necks.
Quote: Now as for lubing necks for bullet seating......I never even thought of doing that. I thought the idea is to seat bullets that will hold the seating position and not push in too easy. That seems a bit risky. ( or is that old school too?
Don’t confuse dimensional bullet hold with friction.
Whatever name you give it.....the hold is from friction. Even a vice turned in tighter just makes more friction, until ridges cut into the part and hold it mechanically.
I haven't run such a test on es & sd, but I did run a test trying to find the best way to get bullets and necks to expand and load with the best concentricity
The LNL bushings do that for you.I deal with concentricity 2 ways.
When it matters the most, I’ll purchase custom dies honed to the chamber specs of the rifle I’m loading for.
For off the shelf dies I use the old trick of putting a rubber O ring between the locking ring and the tool head, which helps the die center itself with the case.
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Whatever name you give it.....the hold is from friction.
Cold weld takes time, a lot of it
The cold weld aka ionic bond seems different in very old cases with powder breaking down. I mention it to ask if there is a different and more correct nomenclature for that process or if it's the same thing with a chemical/gas oxidizer."Friction" is dependent upon multiple variables, and we don't control all of these variables, and creating the same friction by one variable vs. the other is NOT always the same. As I said earlier, there IS a difference between grip, grab, and stick when it comes to friction.
"Friction" as a force is quanitifed: f = µ * N
Where µ is the coefficient of friction, and N is the "Normal force," meaning the force being applied 90 degrees relative to the surface and/or direction of movement. The coefficient of friction, µ , is dependent upon multiple factors.
AND... The coefficient of friction actually changes whether an object is moving or not. For example - if you push a heavy box across carpet, you push hard until the box moves, but once it starts, it feels like it moves easier than it took to get started; because it IS easier to move once it is moving, because the coefficient of STATIC friction is greater than the coefficient of Kinetic Friction (or sometimes called "coefficient of dynamic friction"). Lubricants reduce the coefficient of friction and also typically reduce the difference between static and dynamic coefficients.
So there IS a big difference between creating "bullet hold" by increased tension - increased normal force - which we manipulate by changing neck tension, and creating "bullet hold" by increased coefficient of friction. The transition during preliminary movement and corresponding pressure curve is more stable (or less destabilized) if our primary ignition doesn't include the pressure curve "tripping" over the edge of static friction. Kind of like pushing that heavy box, if it suddenly moves and you're pushing very hard, you might fall down when the resistance suddenly and dramatically changes.
Equally, we don't really have control over consistency of coefficient of friction if we don't do SOMETHING to control it. If we have more carbon serving as lube on one side of the case than another, or we have brass-on-copper stiction on one side but not the other, then we don't have consistent bullet hold, and don't have consistent bullet release. The bullet slides in the neck before the case pressure has increased enough to open the neck from the bullet (which is what we want), so we don't want uneven hold between the neck and the bullet. Doing almost ANYTHING to the necks will cause more uniformity than the arbitrary and random powder residual left from firing. Dry tumbling, spraying, brushing, whatever - as long as the action isn't selective/biased for angular position (i.e brushing necks with something looking like a tiny toothbrush rather than a round brush).
THAT is why it's favorable to create bullet hold - friction - by holding force rather than by coefficient of friction, static or otherwise.
Correcting my own vernacular here, true "cold weld," aka "stiction" happens immediately. But it's also much more rare than folks realize - a lot of folks, myself included, use the term "cold weld" to describe the increased coefficient of static friction between case necks and bullets which largely happens due to slight oxidation of the metals over time, which isn't really "cold weld" - true "cold welds" happen when a surface is sufficiently cleaned and sufficiently polished (and machined) that the atoms at the surface of separate parts are uniquely able to get close enough together that - in a matter of speaking - they don't recognize that they're not actually connected within the same part. That only happens when there is no surface oxidation, but this bonding happens instantly as soon as the atoms get close enough together to "forget" they're not actually together. Molecular level cold welds - stiction - effectively promotes a dramatic increase in coefficient of static coefficient. So when we have REALLY clean brass and REALLY clean bullets, we can have varying degrees of cold weld between cases and bullets, making our friction inconsistent, which, in principle, can (and does) make our primary ignition also inconsistent, hence the difference we see in velocity variability in those side by side tests.
The cold weld aka ionic bond seems different in very old cases with powder breaking down. I mention it to ask if there is a different and more correct nomenclature for that process or if it's the same thing with a chemical/gas oxidizer.
THAT is why it's favorable to create bullet hold - friction - by holding force rather than by coefficient of friction, static or otherwise.
Friction is still friction.
Brasses containing less than 15% zinc can be used to handle many acid, alkaline and salt solutions, provided:
Which could possibly mean that in the case I presented it could be more vulnerable to the degradation I proposed..... why does interaction result in combat.... not arguingCartridge brass, as a material class, typically contains ~30% Zn.
Which could possibly mean that in the case I presented it could be more vulnerable to the degradation I proposed..... why does interaction result in combat.... not arguing
My position was longterm storage could result in an abnormal oxidation condition as a result of the gasses and chemicals presented in #2 of the list provided. This may be the case often presented by slamfire.Who's arguing about brass oxidation...? I must have missed something.
We know cartridge brass oxidizes - the 3 conditions for oxidation of <15% Zn brass alloys might not apply to ~30% Zn cartridge brass, but we know cartridge brass does oxidize. I wouldn't have thought that was up for debate. I wasn't quite sure why you mentioned specific conditions for oxidation of a non-cartridge brass alloy, but info is info, but I'm not interested in arguing that cartridge brass oxidizes, wasn't, and still am not.
Yes, I argued against the incorrect claim made that "friction is friction" above, for the reasons doubly stated in that post.
My position was longterm storage could result in an abnormal oxidation condition as a result of the gasses and chemicals presented in #2 of the list provided. This may be the case often presented by slamfire.
Well, ever since I was a wee lad the old shooters called it "cold weld", so I figure it's kind of grandfathered in. Many terms come to be accepted that way..Yeah, the colloquial vernacular of "cold weld" is misused pretty heavily and pretty broadly, especially by reloaders. As I mentioned in my last, I even use the term "cold weld" when talking about oxidation "bonding" of bullets in brass, which isn't really bonding, but rather the oxidation expands the materials and we get greater interference fit as well as the physical interlocking of the oxidation. Whether that oxidation is caused by internal humidity in the case or by decomposition products of degrading powder, or by external environmental exposure, it's still just oxidation,