ultra-sonic cleaners and seating force

[normmatzen]

I am curious, I have found a problem with seating force when I squeeky clean my cases in an ultra-sonic cleaner.
sure, the outside and inside are really clean brass, but I get more seating force consistency as well as lower seating force when I get lazy and don't clean the cases at all! And, I even lubricate the case mouths with hBN powder in a shot glass of tiny bearings.
I have also cold-welded cases to the mandrel of a collett sizing die with ultra-sonic cleaned cases!

Any one have similar experiences?

 

[kombayotch]

The problem is the cases aren't really squeaky clean on the inside of the neck. There is an oxide layer there due to the powder that burned.

Take a worn-out bore brush and wrap some 0000 steel wool around it and spin inside the case neck. That will remove it and seating will be smooth as silk.

 

[DHD]

I have noticed it especially when I sonic clean and anneal. I got in the habit of chucking a stiff nylon brush in my press and running my cases on it for a few seconds and found my bullets slid in very smoothly. Just as mentioned in the above post, I believe/suspect an oxidation occurs and that is what causes the roughness in seating bullets.

FWIW, I tumble my brass after sizing to get any lube off (and I like the shine), and found that it helps lessen the roughness, but the stiff nylon brush does a better job.

If I did not have borderline Brass OCD (and have all those nice tools), I would just tumble the brass and not sonic clean at all, but the voices won't let me do that! 8)

 

[searcher]

I use moly in many loads and it is much more difficult to detect that "rough feeling" when seating fired (and tumbled to clean only) cases. On those I don't use moly on, I don't so much as brush the necks out. I quit doing it about 10 years ago and found it was not the necessary evil I thought it to be. The evenly distributed residue works well to provide uniformity and is difficult to replicate from loading session-to-loading session using many other "methods".