Stainless media can be had from online retailers that sell reloading gear, from eBay, Amazon, and the online storefronts of the tumbler makers like STM.
I do not have a problem with pins sticking in the flash holes, but they can stick in the necks. The most common size of pins that most tumbling media vendors sell tend to stick in 6.5mm necks.
Pins will stick in primers. Jerry Miculek doesn't deprime before he wet tumbles so he says he disfavors the pins because they break decapping pins, and he uses stainless steel chips instead from "Southern Shine Media." I bought some of those but found they etch the cases (they're very sharp) and they're hard to clean up -- some of the chips are very tiny and light almost like grit or dust and in the slurry they stick to stuff. The pins, on the other hand, are individually heavy enough they stay neat. I bought the chips just for my 6.5mm cases so I don't have to pick pins out of the necks, but I think I hate cleaning up the grit just as much. It does clean up with a neodymium magnet.
With the pins, I find I don't even need the magnet. I just use a Frnk. Arsn. sieve type separator over a 5 gallon bucket and hot water. Hot water seems to make the pins come away from the brass whereas cold water makes them stick to the brass. I believe temperature affects the surface tension and film strength of the water.
I decap before I tumble because water sticks in the primers and leaves the primer pockets wet which causes misfires and squib loads. You can avoid this by baking the brass in an oven. Whether wet or dry, I still hate the slime or grit left in the primer pockets and so I decap them before I tumble and they get cleaned out well.
When you wet tumble, decapped or not, you must dry the brass. Water will ruin primers and powder and you can get misfires, squibs and bore obstructions. Have a good procedure and don't be in a rush to go from wet brass to loaded rounds. Make sure you have enough brass that you can load stuff that's been dry for a long time. Guys will go on long threads about how they dry their brass. However you do it, just be sure to do it.
If you wet tumble cases for a long time, the case mouths can be peened out of good condition. Get a timer that shuts off the tumbler to avoid this. I tumble for 15 minutes, rinse and dry the cases (quickly), then lube and resize. After that, I tumble another 15 minutes at most. Then the cases are dried thoroughly. I see no point to tumbling more than 20 or 30 minutes. It just peens the case mouths. I tumble for 30 minutes or less and I've never seen used brass that was cleaner, nor have I ever gotten it cleaner by tumbling for hours. I'm going to start tumbling for 10 minutes and I bet I still get clean brass. I think a lot of people don't even try that because they were accustomed to tumbling for hours in dry media.
