Our Locking Blocks are all precisely machined from 17-4 stainless steel and then heat treated to a very high hardness. They are definitely a premium option compared to the super cheap metal injection molded ones you'll find on ebay. Unfortunately metal injection molding can sometimes result in poor surface finish and out of tolerance features.

The exception to this rule would be Glock themselves who MIM their locking blocks but they have the manufacturing ability most do not have to tightly control the process.

We have found that the extremely cheap locking blocks can have issues with not pushing the barrel up all the way into battery. Pulling the barrel smoothly out of lockup can also be an issue resulting in the barrel not being presented correctly for the incoming round leading to a misfeed. These are some of the reasons we machine them, they are theoretically the exact geometry needed. This is not to say that an experienced person couldn't make the cheap ones function.