Solution? resetting bullets and that popping noise

[jlow]

I think the best way to look at it is with the approach that there are so many variables , and if 1 could actually discover a good cause such as a corrosive
Ness or other containment then 1 can simply avoid that particular process use gloves for example

This is exactly correct!

Although there are likely more than one possible reason for the hard seating and popping sound, we will never get ahead in terms of understanding what is happening and how to avoid it if someone does not do careful studies to find out.

All troubleshooting strategies should assuming that there is more than one problem lurking, but finding each one and eliminating them one at a time is how progress is made.

 

[22XC Guy]

I have two thoughts;

1) The powder oxidation found is possibly creating crevice oxidation or corrosion type bonding at the brass to bullet seated interface area inside the case neck.

2) One mechanical conclusion would be from the circumferential stress from what the case neck exerts on the seated bullet, causing the shear effect or tearing of materials from an adhesion bonding issue, but some kind of corrosion is noted.

Fired case necks have a rougher erosion surface profile from heat, gases, and flame impingement than a new bullet surface does. This depends which material surface profile is harder; there will always be a smearing of material from one to another.

If the corrosion type can be identified under a microscope, this would speed up the results.

Steve

 

[BoydAllen]

IMO the propensity for this bond to form may actually be increased by the inside of necks being perfectly clean and having all trace of lubricant removed. This may be because unoxidized brass will corrode faster than metal that has a layer of oxide (speculation). As far as the grip on bullets (not related to any bonding) increasing over time to any significant degree, I believe that this has yet to be confirmed, or in any was quantified. Also, from the perspective of my own personal experience, I do not think that any of this can be attributed to simple interlocking of surface texture. The increase in force required to pop loose a "bonded" bullet is too large.

 

[lpreddick]

i had 25 22BRX cases loaded with 69 barnes matchburners. they were loaded 12 april 2012 with .002 neck tension. the cases had been fired twice. the neck was quickly brushed with a nylon brush prior to seating bullet. i seated each bullet .010 deeper and 24 of these cases had a very slight "pop", then the bullet easily seated just as it did when initially loaded. the resistence to the bullet moving could be felt until it released with a slightly muffled mini pop, not nearly as loud as some. i pulled them all and none of the bullet surface that had been in the case had any changes other than being a bit shiney, while the exposed portion of the bullet was a bit oxidized. i attempted to pull a bullet from a case that had been loaded years ago and i had to use ALL of the hornady collet puller's adjustments to get the bullet out after repeated slipping of the collet...the bullet was marred like hell. somebody has probably suggested the perspiration on our fingers(salt), over time, could be setting up a type of chemical reaction leading to a "bond". some of us sweat more than others. i think i'll load some while wearing gloves and some without, wait awhile, then seat bullets...we'll see.

 

[300 RUM]

Today's lab find, the suspect bullet was tested for corrosion using Titration Procedures and a viewing at 200x. Honestly I need to review the results a bit before fully commenting, but as a primarily find for corrosion well there was some just not sure how effecting it may have been(very minuscule)
Also Today I took several of my cases (2 are Lapua and 2 are W-W) that have been both fired approximately 8-10 times and viewed them under a microscope at 30x. I was comparing them for "surface texture" surprisingly they both appeared identical (I will try to provide photos for all). Identical that they all had a lack of those little protrusions that were biting into the bullet on the original sample. Now one possibility for this is due to the fact I F/L size and use the expander ball 90% of the time. What I could see inside the necks were that carbon had compacted into and filled those tiny peaks and valleys to where the protrusions were no taller then lets say 10 microns or smaller.( some things are just hard to judge) Now I need to view some new never fired and a few once, twice etc. fired for "surface Texture" and compare them.

 

[BoydAllen]

I just spoke with a friend who loads ahead for several magnum hunting rifles. (He has quite a collection, that he shoots.) He told me that he puts a little Imperial Sizing Wax on his thumb and forefinger and rolls his bullets between them to apply a thin coat of the wax just before seating , and that this has solved any bullet bonding problems. He also mentioned that it tends to reduce fouling. He is a smart fellow who builds his own rifles, and shoots well, so when he tells me something I tend to listen carefully. He does a lot of experimenting and testing. I like that.

 

[300 RUM]

Ok back at it again.


received some more samples today, yea, a hand full of bullets and a few cases. One thing to mention is I checked the bullets first they were pulled just after the "Pop" was felt and heard.

Anyway this one bullet stood out under the scope at 100x and then at 200x. it seem to have a lot more crystallization then the others i received. Keep in mind the size is "submicron" .1 or smaller micron??

There are other identifying marks that resemble a tearing pattern, this not not easy to identify at this level of magnification, so I will leave at that until further viewing has been completed. I would say there is enough corrosion on this particular bullet to have bonded itself, thats right I would say that if I could find matching particles on the case, but have not at least so far. More Resulets to follow..

 

[jlow]

Interesting results!

One of the potential disadvantage of the current test is we are dealing with live round which requires the bullet to be push/pulled for examination (for safety). Removing the bullet causes a potential distortion of the bullet case neck interface due to their sliding action against each other’s surface.

I wonder if it would be useful to put together some round that are really clean, salt contaminated, or protected by a surface lubricant without a primer/powder. Some of these rounds could be seated to see if they pop and at what pressure, but others simply cut apart after being encased in something like epoxy. The sectioned rounds could then have the bullet lifted from the necks and then their surface examined?

I also wonder if some of the "bonding" effects could be accelerated by heating the rounds (without primer/powder) since all chemical reactions are accelerated by higher temperatures.

 

[lpreddick]

ask and you receive. i made a very slightly salty solution on last sunday...barely able to taste. i dipped my finger in the solution and caressed a 107 gr smk that was polished of all oxidation and discoloration and seated it in a new 6br case after cleaning the inside neck with denatured alcohol and blowing the neck dry. 48 hrs later i adjusted my seater to push the bullet in by .005 and it slid without any noise! repeated this yesterday and very slowly pushed on the bullet and IT POPPED! a very subtle sudden movement producing a vibration(noise). i should have had a control but wasn't expecting what i heard, so i repeated the process except i wore gloves during bullet handling and will seat this one at 48 hr intervals along with the salted one and report later. i handle my bullets a lot and noted finger prints on some that were previously loaded. sodium chloride (table salt) is a potent corrosive agent and makes up a large component of sweat. some people's hands sweat a lot more than others. i am now wearing gloves when handling bullets and am very interested in what i find. the "bonding" we see may very well be a simple chemical process.

 

[jlow]

Using a salt solution is a very good way to go as it allows you to control the amount of NaCl in the neck which might be hard to do using the occasional sweaty fingers. Heating as I suggested might also hasten this.

The only thing is I am not sure that there is only one culprit at work here in terms of this "cold welding". What would be great is to measure the seating force to get that pop and I guess if one can get a very significant increase that would make me feel more comfortable with the one culprit idea.

 

[300 RUM]

my lab tech just gave all of us the evil eye , I brought to her today 6 brand new burger 30 cal 185 grain bullets . today's challenge would be to obtain information on ph reactivity at least on these particular berger bullets . for a simple start going to go to the extreme PH levels starting at 6.5, 7.0, and 7.5 .two bulleys will be dipped in each PH level of just pute tap water modified forand appropriate pH level. incubated at 85 degrees fahrenheit .results to follow next week sometime

 

[BlackEagle]

What are you hoping to discover by dipping bullets in tap water and then letting them sit for a week?

 

[jlow]

300 RUM – sounds like a great starting experiment, should give us some good info. Down the road, I am also thinking that one could do some combo studies with the necks – it’s going to be interesting.

 

[jo191145]

What are you hoping to discover by dipping bullets in tap water and then letting them sit for a week?

Me thinks they're trying to prove the wisdom of that age old adage, "You can lead a bullet to water but you can't make it drink". ;D

Having flunked science I assume they're testing the common most PH levels (Acid-Alkaline) of the human body.

 

[300 RUM]

the bullets will be clean first with 99.995 % alcohol dried and then simply dip into the appropriate solution and then dry in the incubator over the weekend.if the copper is more less reactive 2 1 pH value or another it should show up by Monday or Tuesday or even sooner