my bad, thought we were talking polycarbonate lol
high speed roughing end mill would work best, or a grinding disc, but grinding discs for dremels are usually crap.

But regardless, my chisel can definitely remove metal piston teeth. I also use it to trim mechbox walls when gears are too tight, shave sharp edges off metal bodies, remove material from metal bodies in tight fitment, I even used it to finish boring out my MOE grip for my PTW lol
It's all just a matter of hardness

grinding bit of some sort... I dunno it was a cheap 10$ jobmate rotary... I used it 5 times and the chuck stripped so I can't change bits anymore.... :P

If you can slide the entire rack out of the piston it makes it extremely easy to remove the teeth with any file or grinding bit. Just use some vice grips or vice with something on top ( so as not to leave marks in the rack with the grips) to hold it down.. cheaper to change the shitty jobmate tool than it is to buy dremel bits. lol.

I just use a cutoff disk and a steady hand. Wear glasses and a cutting disk is meant to cut on its edge, not its side...so not lateral loads, some are pretty brittle and can snap.

+1, had to pry a shard of that crap out of my arm before..

My next hurdle. My teeth are flush with the outside face of the piston. Attachment 33573 How do I slide the rack out? Or do I need to just use surgeon like precision. Would there be an impact if I trimmed the plastic on either side of the teeth to get better access to the teeth?

remove the piston head and the whole rack should slide forward and out.

when you put it back in, don't forget to epoxy it in there when you are happy with your aoe adjustment. :P

What is the purpose of the epoxy? My rack just slid right out of the piston.

So I have done my trimming, rebuilt my gun and found that there was a lot more tension on the spring than normal and that the gun wouldn't cycle (could be related to my shim job). Is this common? I realize that the sorbo takes up space but I wasnt sure if this is a common issue with AoE correction. I am 90% sure that I currently have a M100 spring installed.

racks have been known to plow the pistonhead completely off the piston. Gluing it in with epoxy prevents that possibility and adds some strength to the pickup tooth (helps prevent the pickup tooth and the back of the piston from shearing off. Though with 120 springs, it's pretty uncommon if your piston head is well secured. Not glued, the rack relies on pushing against the pickup tooth or the piston head to stay in place. When you glue it to the piston, the rails where the rack slide into place are now bonded to the rack and help take some of the stresses off the ends of the rack.