Bullet to neck "Welding"

[rodell]

I pulled out some loads from 2015 in 300 Weatherby to get ready for this year's Elk season. At sight in the velocity was quite a bit higher than my notes showed. I had loaded some new rounds using the same recipe and the velocity was 300 fps lower ... hmmm.

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. We're talking actually stressing the press to pull some of the bullets. I ended up pulling every cartridge and about half came out easily, and the others took considerable effort. The velocity difference for those I did shoot was clearly shown on the target, too.

These were Barnes TTSX's loaded in squeaky clean cases and I clearly need to start adding mica or graphite or something else to prevent welding if I'm going to keep loads handy. I haven't seen the phenomenon with other brands. I asked Barnes what the factory does to prevent this but got no answer.

Does anyone know what the factories use? Any ideas how to keep neck tension consistent while adding lube?

 

[desertcj]

I am usually shooting moly coated bullets and I haven't had that problem. Most people dont use moly anymore though. I also don't clean my necks squeaky clean. Just how they come out of the tumbler and there is still some soot on the inside of the brass which I'd say probably helps?

 

[TXbaldhunter]

I ran into a problem like you,so to keep it from happening I changed my ways.Now after I resize my brass,I put them in the tumbler to clean up and remover any case lube.Then when I get ready to load,I swab the inside of the case necks with powdered graphite on a cotton bore mop.Since I started doing this about five years ago I have not had anymore issues.

 

[preacher]

Another trick is to take any ammo you have had loaded awhile, and just seat them a hair deeper in the press. this breaks the seal and does not harm accuracy. Bear in mind, I don't shoot game or compete at long distance, so can't say what is happening way out beyond 400yds .

 

[TXbaldhunter]

Yes seating a hair deeper really helps.If you ever have to pull any bullets,seating deeper before you pull them really helps.

 

[baltz526]

All my hunting ammo gets a Lee crimp. In effect creating the weld you think is causing an issue.

 

[rodell]

All my hunting ammo gets a Lee crimp. In effect creating the weld you think is causing an issue.

I can attest the Lee crimp does not increase muzzle velocity by 300fps. Not that I dont like Lee FCD crimps, they are very consistent. I've run lots of crimped vs. not crimped comparisons.

Some of the bullets I pulled were in there so well it stressed the press to get them out.

 

[walkinhorseman]

Some competitive shooters wil pre-load large quantities of match ammo, seat them long and bump back the morning of the match.
There is a product called Neolube that is used to prevent galling of stainless threads. Colloidal graphite supported in isopropanol. Dries rapidly. It can be applied to the inside of new case necks with a Q-tip.

 

[preacher]

The Neolube sounds like a great product for this application, thanks for the tip!

 

[ShadeTree]

If I have older loads I'm worried about, and the seating depth is right on the money for that gun, I do essentially the same trick as Preacher, except in reverse. I jump them out .010 or so with an inertia bullet puller, then simply run them back through the die, seating them back to the original depth. Problem solved.

 

[diverdown]

A good number of years ago I spoke with Hornady in regards to this. One of their Technicians explained it in a way that made perfect sense. You have a brass case and you have a bullet that is of a different material. Over a period of time the different metals react in a molecular fashion. This causes what you are getting. If there is any type of lube or other material coating the inside the neck (could be residual burnt powder) it will slow if not stop the process. The same will happen in a different fashion with brass cases. In the past I attempted to size a number of Winchester 7MM mag that were from the early 70's. A lot split and the sizing was difficult. As it turns out the materials used in the manufacture of the cases caused the molecular structure to change over the years and caused the brittleness. Not all cases fall in this category, it's the material used in making them. I hope this helps.

 

[ShadeTree]

A good number of years ago I spoke with Hornady in regards to this. One of their Technicians explained it in a way that made perfect sense. You have a brass case and you have a bullet that is of a different material. Over a period of time the different metals react in a molecular fashion. This causes what you are getting. If there is any type of lube or other material coating the inside the neck (could be residual burnt powder) it will slow if not stop the process. The same will happen in a different fashion with brass cases. In the past I attempted to size a number of Winchester 7MM mag that were from the early 70's. A lot split and the sizing was difficult. As it turns out the materials used in the manufacture of the cases caused the molecular structure to change over the years and caused the brittleness. Not all cases fall in this category, it's the material used in making them. I hope this helps.

Maybe you already did this and still got those results with your particular brass. But what I do in cases like this is anneal old brass before I ever attempt to size them.

About a yr ago I picked up a grocery bag full of used 6MM brass, some likely once fired, and some abused looking and questionable, but only $15 so I grabbed it. I sorted them by brand, threw out the questionable ones, and then tumbled just the mostly old and badly tarnished Rem brass for now. I picked out some to get started using and annealed them first to make the hard brass more malleable before getting stretched and squeezed in a die. I don't recall losing any of that batch in the process.

Working with old brass it's almost inevitable to lose some, it's gonna happen, but it makes sense to me that annealing prior, significantly reduces that amount and extends the forward life in subsequent reloads of old brass.

 

[diverdown]

you answered the question perfectly. Annealing the brass changed the structure of the brass. I anneal a lot and it usually eliminates any issues with split cases. I worked with the 7MM cases prior to doing any annealing. (wasn't familiar with the process at that time.)