Home Forums Reloading Big Game Rifles Cold Weld Solution

I've never like to leave my ammo loaded for too long because the neck tension would increase and accuracy would suffer from cold welding (bonding) of the bullet and the neck. I've got a buddy that's a chemist and he mixed a few things together and made some quick drying liquid for me to apply to the inside of my case necks with a q-tip. He said this should serve a dual purpose of lubing the neck and protecting it from bonding. I used a 7-08, 223, and 308 as test calibers. I also loaded an equal amount after lubing the necks with imperial dry neck lube and hornady one shot. One group was also only tumbled then the necks brushed to see if the carbon in the necks would prevent bonding. All cases except the tumbled and brushed group were tumbled in corn cob media, deprimed, ultrasonic cleaned, annealed, necks brushed, resized, lube applied then loaded. I loaded all the bullets using Wilson dies on a 21st Century Hydro Press and recorded the force it took to seat each bullet. I then marked each case and put them up in my reloading room in my house where they have been since then. One thing to note was that with this new lube, seating force was dramatically less than each other group, with the unlubed cases being the worst. Yesterday, I took each bullet from every group and recorded the force it took to seat the bullet .020 deeper in the case. If a bond was present it was very noticeable by a pop before the bullet would move. Not one case in any caliber with the new lube had bonded to the neck and popped before moving. The new lube seating force required to move the bullets deeper was greatly reduced over the other 3 groups. 60-90% of all bullets in the other groups had bonded to the neck and popped before moving with several w not moving at all and maxed out the 100lb dial on my gauge. This was just a test (7 bullets in each group in each caliber) to see if it would actually work but we are planning on doing a larger, detailed test this year and documenting everything well. If the next test group works as well, we might try and market this stuff.

Seems this treatment would likewise facilitate unintended movement of the bullet in the case.

The results i saw was that it took the same amount of force to move the bullet .020 as it did 6 months before, and each bullet seated within 5lbs of each other. The other methods were 2-4+ times the force was required to move the bullet and seating force varied by 50 lbs in some cases from bullet to bullet. What that tells me is you start with .002 neck tension, you still have the same tension 6 months from then and not some unknown amount depending on how much bonding has taken place.

Yet you can pull ammo that has been loaded for 40 years, and their is no evidence of ‘cold welding’.

New brass is normally mirror polished inside the necks and smooth as butter because nothing has been pulled through it. Once you pull and expander through the neck or expand it up on a mandrel you create small ridges in the neck. When seated with pressure these ridges cut grooves into the jacket of the bullet and accelerate the problem. Load one with your normal procedure then pull the bullet and look at the jacket and you will see the streaks. Load some bullets long and seat them deeper a few months from now and report back.

Upon firing, case expands, right?

Was there any difference in group size between the lots when fired?

Good question.

I have not fired them. I'm going to let them set for a few months and bond back then shoot for groups. Rancho: the case necks expand upon firing but if there is a bond present, the bullet gets held longer. Ive taken my match rifle and shot rounds that seated with different pressures over a magneto speed. Loads with increased seating pressure were faster than loads with less and impacted higher on the target at 600. I then grouped bullets that seated within 2lbs of each other and shot a 2" group at 600 with an ES of 8 fps.

Not buying it.

I've been using imperial wax on bullets before seating to eliminate cold welding since JB recommended to me. I load large batches now and hunting loads can sit for a while. Works well and the seat a lot easier too.

There is a saying in the millwright trade. "Never put it in dry!" I can't think of a scenario off the top of my head where this does not work.lol I ve been using imperial sizing wax for years to lube bullets prior to seating and never seen a downfall to this method yet.

So, cold welding increases speed? I'll load several hundred bullets now and crimp. That's gonna make my rifles shoot flat all the way to 1k, which I have always wanted to try...

Not trying to bash your theories, and I see that on numbers it may differ and cases/bullets may "weld" at different speeds increasing divergence. However, this may be what in medical terms we call "statistical significance without clinical relevance". (or ballistic relevance)
Consistency is the name of the game for accuracy and good groups, but there is the phenomenon of diminishing returns on effort done. Make sure you are not at the curve's turning point and plateau.

Lots of match shooters seat bullets long and do the final seating right before a match to avoid cold welding.Cold welding is enough of a factor to warrant attention by match shooters.to average Joe,probably not.