[Trev140_0]

All BBs are made with Plastic Injection Molding machines. Husky and Engel are the top end. These are moulds that are made with thousands of cavities of the bb. Like a giant ice cube tray.

The Mold is made with EDM. (Electro discharge machining) electodes which burn the half sphere into the half mold. Electrode is either graphite of copper. Don't get me going on that. Big difference.

The mold is then polished to get the master. Keep in mind a plant will have dozens of injection molding machines AND MOLDS.

The seam is present when the bb's comes out. So to get this is out, they are put into a vibratory finishing process. Giant hopper with a polishing media slurry. Dozes of them.

Here is where it goes for a shit:

1) Multiple molds. As the electode wears during making the mold, the various moulds vary
2) As the cavity wears, the mould becomes BIGGER. Left un changed or cheaping out, the BB's get BIGGER. Keep in mind there are dozens of machines spitting out bb's
2) Media for finishing varies over time. Giving a different surface finish. Also a bb that went in starting at say 5.97" may grow to 5.96" after "x" time in the finishing machine. That will vary when the starting bb is larger or smaller. The ability for the media to "work" will diminish over time.
3)Temperature during inspection of the first article. Expansion coefficient of the steel in the mold etc etc.
4)Temp of the plant making the bb's. Is it temp controlled or 140 degrees in the dead of summer?

To me the bottom line is use what works and don't fuck around. Jam your gun on a piece of shit bb and you can turf your grearbox, WHATEVER the bb "brand" is.

I issue Elite Force at our Field. I have zero complaints. I suspect it has to do with having a 5.95" nominal tolerance. Elite force is 5.95" +/- 0.01". NOT "as close as possible to"This puts the baseline in a spot that reduces the chance of jam for tighter tolerance set ups.

Find what works, then stick with it. Spend your time, money and energy on other stuff.