I have a box of Missouri Bullet Company coated bullets I am thinking of reloading for the 44 DE.

Any reason no to use?  

From what I am reading they should be GTG, but looking for opinions.

Doc

I have not tested these coatings in a firearms environment, but it is my opinion you would be better off with the properties of metals (e.g. copper) when heat/pressure is involved pushing it through a gas port.  Because polymers flex, and their cohesion is higher than their adhesion usually, it is going to be harder to break off accumulations inside of an "anything".  Heat and time will age the polymer more than metallic accumulations, but that metal will be more likely to flake off and move through than a polymer.
On the flip side, you MIGHT be able to use a solvent on a polymer in ways you can not on lead and copper inside the Desert Eagle gas port.

This is not something I want to experiment with however... and as Garret said, there are many kinds of polymer coating and they could change formula over time.  What works today might not work tomorrow, where copper jackets and plating are pretty consistent.

I would like to know how it goes over time if you really run a lot through it though. :)

MrBlackCat

I don't care for coated bullets.

I have had the coating wear off and expose lead in the barrel.

I also have seen many fired pistol bullets with the coating worn off in the grooves.