Here is the front barrel support. This part accomplishes a few objects. It supports the front of the barrel, is the guide for the recoil spring, acts as a seal for the escaping gas and locks the upper receiver together. So while a simple part to make the tolerances have to be maintained. This is a picture and solid model of the part.
There were two of these made and different methods were used to do it. The final method is the one that we will use when we cnc machine them for a production run. I must apologize in that I did not take a great deal of pictures while making this part. The time constraints required that it be made in a hurry to take this project to the next step.
The first method was to turn the out side to the proper dimensions then cut it off and bore and ream the inside.
While this method worked the concentricity was a little out, but still with in spec. So a different method was used the second time around. With this one I bored and reamed the inside of the part to the desire dimensions and then turn the out side between centers to. This allowed the inside and outside to concentric.
the final step is to cut out the locking groves. This was accomplished with a rotary table.
Hope you enjoyed this post. I am a little behind on post, but up to speed on the project. In the last 2 weeks two test ( for function) barrels have been made as well as the gas piston. The rear top cover tooling has been made and fitted. The trigger guard and safety attached. It is starting to look like a rifle. There is more to post so please stay tuned.