Cold welding of bullets in case necks and moly coated bullets
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BoydAllen
Gold $$ Contributor
JRS,
Vacuum....really? And just where did this vacuum come from? The pop comes with slight movement of the bullet within the case neck. Perhaps you have not experienced this particular phenomenon? There is little doubt that some sort of bonding has taken place, whether it fully fits the definition of cold welding is up for grabs, but bonding it is. The amount of force it takes to force a bullet a little farther into the case is considerable.
Boyd
Vacuum....really? And just where did this vacuum come from? The pop comes with slight movement of the bullet within the case neck. Perhaps you have not experienced this particular phenomenon? There is little doubt that some sort of bonding has taken place, whether it fully fits the definition of cold welding is up for grabs, but bonding it is. The amount of force it takes to force a bullet a little farther into the case is considerable.
Boyd
Brians356
Gold $$ Contributor
When did the supposed vacuum inside the case form?
When seating a bullet, if anything internal pressure (opposite of vacuum) is created since the bullet compresses the internal air (assuming no leakage past the bullet or primer.)
Over time, again without leakage, that pressurized state would remain static indefinitely. Where's the vacuum?
Suppose later we attempt to pull that bullet. The pressure would be relieved as the bullet which created it is backed out of the case. The internal pressure is acting (however slightly) to assist in moving the bullet. Why would it "pop" from anything besides a mechanical bond breaking?
Now assume there is leakage. When the bullet is initially seated, pressure is created, but over time leakage would equalize internal and external pressure. Where's the vacuum?
Then suppose we pull the bullet in that equalized pressure state. A temporary vacuum is formed (assuming leakage is very slow) while the bullet is being pulled, but you're not going to hear a "pop" until the bullet clears the neck, and outside air can rush in.
If Boyd and others hear a "pop" when seating a bullet only fractionally deeper, there's no way that can be attributed to an internal "vacuum". Neither can it be attributed to internal pressure, IMO, unless you believe the internal air will suddenly rush past the bullet as soon as it moves a fraction. If that were the case, why would any pressure have built up inside the case in the first place?
When seating a bullet, if anything internal pressure (opposite of vacuum) is created since the bullet compresses the internal air (assuming no leakage past the bullet or primer.)
Over time, again without leakage, that pressurized state would remain static indefinitely. Where's the vacuum?
Suppose later we attempt to pull that bullet. The pressure would be relieved as the bullet which created it is backed out of the case. The internal pressure is acting (however slightly) to assist in moving the bullet. Why would it "pop" from anything besides a mechanical bond breaking?
Now assume there is leakage. When the bullet is initially seated, pressure is created, but over time leakage would equalize internal and external pressure. Where's the vacuum?
Then suppose we pull the bullet in that equalized pressure state. A temporary vacuum is formed (assuming leakage is very slow) while the bullet is being pulled, but you're not going to hear a "pop" until the bullet clears the neck, and outside air can rush in.
If Boyd and others hear a "pop" when seating a bullet only fractionally deeper, there's no way that can be attributed to an internal "vacuum". Neither can it be attributed to internal pressure, IMO, unless you believe the internal air will suddenly rush past the bullet as soon as it moves a fraction. If that were the case, why would any pressure have built up inside the case in the first place?
brians356 said:
It's not a "weld" its a bond. Neutralizing the bond makeup is the way to prevent it. Along with smoothing the inside of the case mouth so that there are no ridges to dig into the bullet jacket.
Brians356
Gold $$ Contributor
jsthntn247 said:
Thank you. Mightn't we now rephrase the subject line of this thread?
This discussion makes me grateful that my most accurate loads, which I have stored in fair-sized batches, have moly-coated bullets. "Weld this, sucka!" *
[* Next someone's going to exclaim that molydenum disulfide is hygroscopic and induces corrosion - and hence "cold welding". <sigh> ]
BoydAllen
Gold $$ Contributor
Getting to the plastic inertial puller question, I really don't know, because if I cannot remove a bullet with ordinary force and reps, I usually assume that giving it a little push into the case will make it come out a lot easier. That is for my occasional foray into regular reloading. I do most of my loading for a PPC, at the range, and if any bullets need pulling, it is done there, while they are fresh in a case neck. For this, I use a Hood bullet puller (out of production) that was made specifically for PPCs and one of those three caliber bullet pullers that you grip like pliers. When I have run into "cold welding" it has been when I was disassembling or checking out some old reloads for one of the various rifles in my safe that have seen scant use since I got a truly accurate rifle. How did that go, something about only accurate rifles being interesting? Actually I also have a bench style, tight necked .222 that also falls into that category.
TonyinKY
Silver $$ Contributor
I encountered this "situation" once several years ago on 30BR loads with Tungsten Disulfide coated Knight bullets. I had left 4 rounds loaded at the end of the 2010 shooting season (maybe October?) and at the beginning of the 2011 practice season (maybe late March?) I went to pull the bullets (kinetic) so I could resize and reload the brass back to "match" specs. It took a lot more force than usual to release the bullets (bullets aren't very deep in the case) and the bullet area that was in the neck looked like it had a Tungsten Disulfide "plating" removed. I discarded those 4 pcs. of brass and vowed to never leave my match rounds loaded for more than a month.
Last month I got out that set of brass and had several (maybe 15?) rounds loaded from the end of the 2011 season. I expected to find the same "situation" as I had earlier especially since it had been loaded for over 3 1/2 years. All bullets pulled easily and looked as good as the day I loaded them. I am freaky meticulous when it comes to my reloading concerning every aspect from brass prep to bullet coating. The greatest variable that comes to mind is the possibility of a humidity difference of when the rounds were loaded.
There was certainly a fusion of the brass, Tungsten Disulfide and copper. Fusion = The merging of different elements into a union
Last month I got out that set of brass and had several (maybe 15?) rounds loaded from the end of the 2011 season. I expected to find the same "situation" as I had earlier especially since it had been loaded for over 3 1/2 years. All bullets pulled easily and looked as good as the day I loaded them. I am freaky meticulous when it comes to my reloading concerning every aspect from brass prep to bullet coating. The greatest variable that comes to mind is the possibility of a humidity difference of when the rounds were loaded.
There was certainly a fusion of the brass, Tungsten Disulfide and copper. Fusion = The merging of different elements into a union
As I stated earlier, I have been aware of this since the early 80's. Since I am not a competition shooter, and only hunt rockchucks with a fervor, I only prep cases but do not reload them until anticipating a shooting trip.
One thing I do, is to run the expander plug into each pre sized case to equalize the neck pressure, as cases sitting for months, have a change in the neck size thru contraction. It gives me accuracy better than what I need, but I just do it as a precaution.
I surmise that whether the problem comes from the contraction of the brass or a form of interaction from like metals causes uneven neck pressure.
One thing I do, is to run the expander plug into each pre sized case to equalize the neck pressure, as cases sitting for months, have a change in the neck size thru contraction. It gives me accuracy better than what I need, but I just do it as a precaution.
I surmise that whether the problem comes from the contraction of the brass or a form of interaction from like metals causes uneven neck pressure.
BrianS----I hunt in Oregon and N. California. There is no way that I could erradicate the populations if I tried. They inhabit huge rock piles cleared from the fields which is the best cover one could ask for. They have alfalfa to eat from April thru September and get absolutely hog fat. Once they have been hunted, you have to outsmart them and the average guy would not know how.
Brian, I am not capable of shooting at over 500 yards. I mainly shoot 20 calibers along with a 223. We shot 4 at over 400 yards this year, my son killing a big chuck at 458 on the second shot. Frankly we never tried shooting them past 400 yards until the 2015 season. It is the primary reason I want to keep living and enjoying life.
Hey this 7 pages of infighting and boring talk about whether bullets stick in cases or not finally went somewhere fun!Call it cold weld I see as corrosion bonding Two metals that bond together because of oxidation of metal. The larger of the bearing surface the harder they are to move.
Any body that has used a Bersin Tool see it all the time. Check Bersin tool. It was a hot tool 15 years ago. Larry
Any body that has used a Bersin Tool see it all the time. Check Bersin tool. It was a hot tool 15 years ago. Larry
swd
Silver $$ Contributor
Thanks Lenard. I've got a Sako heavy barrel 243 also. Still shoots pretty good but the throat has moved forward a lot. I might rebarrel into a 6 Dasher. That should be rough on chucks. I shot a few with my 17 Rem this year too. Anything inside 400 is fair game with it. I still have about 40 rounds I loaded up for chucks this year. I sure hope they don't weld themselves together for next year. How late in the season do you hunt chucks?
Metalergists will always tell you that like metals put together will have a chemical reaction to one another. Whether it is caused by moisture or not, it makes no difference. No one has said it works all the time. A good portion of the problem, is that brass does not all have the same alloys, the reason that some is better than other brands.
I have pulled bullets from cases after testing various loads. Some pieces of brass will contract more than others which is easily detected when pulling the bullets. Some are very hard to pull. In my book, the hard to pull cases/bullets, have more neck tension than the others.
SMD, you have a private message.
I have pulled bullets from cases after testing various loads. Some pieces of brass will contract more than others which is easily detected when pulling the bullets. Some are very hard to pull. In my book, the hard to pull cases/bullets, have more neck tension than the others.
SMD, you have a private message.
Did you mean to say "unlike" metals (dissimilar) as in galvanic reaction of which moisture could be the electrolyte required to initiate the reaction? I'm wondering if the salts from sweat from your fingers could be the catalyst. My eldest is a "ruster", every bare piece of steel he handles leaves rust fingerprints or worse. On occasion I have pulled bullets he reloaded and they could not be pulled with an impact puller. Note that they were definitely not crimped. These pulled bullets always have a narrow black ring around the bullet and underneath that black substance there is a definite groove that takes a few passes with steel wool to remove. I would think that besides body salts, any cleaner or oil that has a high Ph might also serve as a catalyst. Remember also salt tends to attracts moisture (humidity).Lenard said:
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