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I got out some loads in 300 Weatherby that I assembled in 2016 to sight in my Elk rifle. The velocity was quite a bit higher than I remembered, and, I couldn't match it with some new loads to go with them by a few hundred fps.

I pulled a couple of the bullets with a collet puller and they were really in there! A substantial difference in force from pulling "fresh" loads. Clearly the reason the velocity was up there.

These were Barnes TTSX's loaded in squeaky clean cases (wet tumbled and my notes don't say anything about excessive seating force and I wouldn't have continued if they didn't feel normal).

What can I do to keep this from happening once again (besides shooting up all my loads!) and still keeping consistent neck tension?

I've had this happen with older military ammo.....put the ammo in the seating die and push the bullet about .030 deeper.....this will break the existing neck tension issue.

How to prevent it?.....maybe someone else knows

A squeaky clean interface between the surface of the bullet and the surface of the case-neck creates near-ideal conditions for diffusion bonding. I leave my cases grotty, doing no more than washing after use. I don't clean the case lube off before seating bullets either. It seems to work ;-)

Squeeky clean is the problem. One of the reasons I don't wet tumble. Its good to have a little soot on the inside of the cases... Never hurt a damn thing and I load some pretty accurate ammo.. Just sayin..


Nothing wrong with it being clean, as long as it's the outside. Not the inside... That or you can lube the inside with graphite before seating the bullet. An extra step for you guys that wet tumble, but it may be necessary. I'll continue to keep using media to tumble my brass... And no, I never leave case lube on my cases. That's just stupid...

I have had no issues wet tumbling...

That's one of the problems with wet tumbling, the cases get too clean and you end up with bonding/cold welding after they sit a while. You need the layer of powder residue in the neck from the previous firing or some other way of preventing it. I've read some of the target guys will dip their bullets in imperial dry neck lube (graphite) before seating the bullet to prevent it if they're not going to be using the ammo soon.

I don't know about wet polishing but after tumbling with a liquid polish in corncob I tumble in clean corn cob with a pinch or two of paste wax scrapings. Removes any remaining polish and adds a very thin layer of wax to prevent tarnishing. I suppose it leaves a layer of wax inside the neck too. Never noticed a cold bonding condition anyway.

And my ammo stays pretty.

You just got to watch out for those little stainless pins...... I found some in some of the 308 Norma brass you sent me... Get one or 2 of those going down your barrel at mach 90 and you'll (or your barrel, I should say) will have issues...

Yes, or they will load long and bump back to their OAL at the shoot, or right before the shoot...

Use powdered mica in the neck unless you are going to shoot ammo within 3-6 months.

Nah they make your bullet go faster

The big problem is not shooting up your loaded ammo fast enough.

I like JBs method, shoot dirty cases. Wax, Hornaday One shot, mica, moly, graphite all work. Graphite can back fire as it attracts moisture. Last bunch I did I wiped the bullets down with Dyna Tech Gun Coat. A shot of Corrosion X on the bullets works too but always test fire as they can act like you are shooting with an oily barrel.

Last brass I wet tumbled, I used about two jiggers of Turtle Wax "Zip Wax" which is car wash that has wax in it instead of the usual couple of squirts of Dawn dish detergent. Brass came out looking good, and hopefully there's enough wax residue to prevent tarnishing. It might even prevent cold weld, but it will likely be a long time before I have any confidence in that idea.

I shoot nothing but moly plated bullets, & I never brush or touch the inside of the case neck.

I've pulled pullets from 2,3,4+ year old ammo, and the bullets slide out like they were loaded yesterday.

Some factories use a product called "Black Lucas" in the neck to prevent cold welding(fusion).

I lived out West for 30 years never had cold welding. I moved back South, and I have seen cold welding on my own ammo twice. Moisture maybe a factor.

On hunting ammo that I want to load 100 of, I barely seat the bullets in the case, and when time comes, I measure OAL to kiss the lands(or what ever bullet jump that the barrel/bullet likes best), seat the bullets. This seems to be a good system.

Midway used to sell a little box which contained mica powder and had places to mount bore brushes in a vertical orientation. One dipped the mouth of each cartridge into the mica and then over the brush to clean out the excess. It was marketed to reduce drag on the expander button as the case was pulled from the sizing die. But also served to give e a little layer of lubes between case neck and bullet.

I do not tumble my brass to a new sheen. A couple hours in ground walnut (lizard bedding) in a vibrator, and the finish is usually still a bit dull. And I now moly everything centerfire. And they definitely do not weld to the case.

But I ain't holding my breath while we try to talk anyone into taking up moly plating. I'll just say, I love it.

Boy howdy, ain't that the truth.....gets old defending your position...........

Laffin' here....I am a moly user and have a good system so it works for me, long strings between cleaning.

As for the cold weld, yep, naked metal without any kind of lube will tend to "bond" or need to be "broken free" in a suprisingly short time if there's any force on the surfaces. I've seen it on flat surfaces where just a hunk of metal was laying upon another, and had it happen early in my handloading (before moly) when I'd loaded some "squeaky clean" virgin brass and shiny shiny bullets. Early it shot fine, but I was slow going through the batch and sure enough, I got some wild flyers and flat primers, it wasn't until I tried to pull a bullet and see what my powder charge was, that I realized there was an issue. Couldn't pull, but I could "pop" it downward about ten thousandths and the rest shot fine. But that was a lesson.

Definitely a problem. I load enough for sight-in and then to take on the hunt. Invariably I have a bunch left over, but not enough for the next hunt! These "sticky" ones were loaded in mid-2016, so they weren't THAT old.

When I wet tumble, I use a little armor-all car wash and wax as my detergent. Apparently it does NOT leave enough residue to prevent the sticky problem. I did like the 300 fps higher velocity, who knows what the pressure was. They were also really, really accurate.

I'm going to pull everything I have and start over. I need to have some loads ready at any time.

I wonder how the factories prevent this problem? JB?

I just wipe the brass down, and seat the rounds long.
Long enough it is obviously unworkable. Then just prior to use seat the bullet correctly.
I don't know why this has become an issue, but it definitely is. If pressures appear to jump , I will seat the bullet deeper into the neck .There is a audible' pop' .
I don't tumble the cases- never have and clean the necks sparingly. My experience

Really, really accurate and a 300 fps increase using a little Armor-All wash and wax ?

Yeah, right.

I emailed Federal once, asking what they do to prevent cold weld in factory ammo. The response was basically a non-answer.

You don't need to pull. Simply seat them the slightest bit deeper, just enough to hear them "pop" so that the weld is broken. Then go shoot them up.

Then be sure not to clean the inside of the necks, leaving the powder residue intact. You will eliminate your problem.

I'll take a guess, what the hell. When you draw brass or swage bullets you need a lubricant. Just clean off the bulk of it with a tumble in clean media. Which I read about a bullet manufacturer (Sierra?). I remember because a thorough cleaning made moly adhere better.

Absolutely, you need to degrease. I wash with a mix of Orange Glow and Dawn.

Humidity is a no no as well.

I had some old oxidized bullets and cleaned them up with Never Dull and they haven't oxidized any further or cold welded. Not sure what is in Never Dull but there was enough left on the bullets to prevent oxidation. It would be easy enough to throw in a wad of Never Dull if you were dry tumbling.

The inside of my cases are clean, but I molly coat all of my bullets. No problems shooting ammo I loaded 2 years ago.

So, I got out all of my 300 Weatherby loads starting from 2015 and pulled the bullets. All of them.

Pretty much everything that was more than 2 years old had some of the bullets welded. I stressed the press getting some of them out, and then the next one would come easily (similar to the brand new loads). Clearly a problem and clearly more than a few cartridges. I don't know why some did and some did not "weld". Given the increased pressure and velocity I saw with the welded ones, I'm glad I cleaned them out. I don't need to be a test pilot.

All of these were Barnes TTSX bullets of varying weights. I wonder if the Barnes bullet material is more likely to weld than some of the alloys? An email query to Barnes about welding with new brass went unanswered.

I'm clearly going to have to coat the necks or the bullets as I rebuild my stock. I need to figure out a consistent method.

Copper bullets were more likely to weld and sooner than gilded metal bullets in my experience. Even some bullets like Swift A-Frames and Kodiak that are gilded but seem to have a higher percentage of copper were more prone to weld. Ammo that has been in airplanes also was more prone. I guess they got de-pressured and then when they normalized pressure they took in some humidity. Motor mica definitely helped to reduce the cold welding or corrosion. Same for Hornaday One Shot lube.

I am definitely going to check my older rounds.

Has anyone tried simply spraying the bullets themselves with Hornady OneShot to prevent welding?

I shoot dirty brass.... LOL. Clean brass is a waste, OTHER than trying to find it back on the ground from an AR or the like....

Hunting stuff never really matters much to me, but on target stuff for matches if I was worried about it, then I'd load like 5000 rounds and leave them all long seated. Then as we got to using em just seat the rest of the way and shoot at the next match.

Or, a matter of pride in one's personal craft. No reason to wash your pick up either.

I also take pride in not cleaning my brass - never saw the point of doing that except to make it shiny for the sake of making it shiny. Does it affect case life - no, does it make it easier to detect cracks / incipient head separation - no, does it make it easier to find the brass in the dirt - no.

This works like a charm and is so easy to do. Not sure how old the oldest loads I have that got this treatment but easily 10 years old and no problems.

I wash it to get any grit/dust off it, but otherwise like you I don't see any point in making it shiny. Not only does it not make it work better, but the patina a case develops is actually slightly protective. I see no good reason for adding a process step, time and cost to do no more than remove that. Same goes for cleaning residue out of primer pockets, another process step for which I've found no benefit.

I spray the case necks inside and out with One Shot before sizing, and leave the stuff on through charging the cases and seating the bullets. It (plus a certain amount of powder residue in my case necks) seems to do the trick to avoid any noticeable diffusion bonding, and without adding the step of spritzing the bullets with the stuff.

I wipe it off the finished rounds, which gives me the opportunity to give each round a quick once-over before putting it up ready for use, or storage.

Crank your seating die down 0.010", break the weld and move on with your life.

I have 4-5 gallon buckets of 223/5.56 brass and I wet tumble it so I can sort it and get lc and r-p brass. But I pretty much clean all my brass anyhow.. some are lazy or don't have the equipment to clean there brass, me I have the equipment to do it so why not clean it.