Madbull M203 shell Lube
 

So I learned a valiable lesson. M203 shells don't use silicone oil. The ball bearings keep falling out now so I need a recommendation for a good grease that will hold in the bearings while still providing good lubrication. I have thought about various airsoft greases (western arms sex grease :D) but I figure if anyone has tried something from a canadian tire or somewhere that seemed to work really good then I will try it.

Try silicone dielectric grease. It's sticky, and should be 100% compatible with your o-rings. And it's available at Crappy Tire.

Thanks for the advice. Bought some tonight and just finished putting it back toghether and testing. Works like a charm now!

Don't they just stay in anyways?

And if you mean when you're putting them back together, get a KA cartridge repair/reload kit, they work wonderfully!