IIRC, Charlie's first lube pumps used a "head" that he soldered up from pieces of brass, an aluminum body tube, and a brass end plate that the threaded rod engaged through. The rest of the small pieces were of steel or brass as appropriate and Charlie's individually fitted dies were made of aluminum... he was adamant about that. I have one of 40Rod's Delrin dies though and it works great, I just couldn't tell Charlie!
Once he got going on a semi-production basis, Charlie had a casting made for the heads and made up tooling to finish it off like the pieced-together version. This was not only quicker and easier, but probably quite a bit stronger as well.
Like everything else Charlie ever did, he studied the problem and solved it to what he considered to be the best end point. You may not have understood all the whys and wherefores, but you could be sure it would work when he got done.
I have used pumps I got from him (whole or parts to build DIY, but that's another story) ever since I started shooting, and if I have a bullet I'm using a lot, it seems to be the best way to go. I do have one of the copies of the original Pope-made pump that Joe Ruth made up about 30+ years ago and since it is such a pretty brass unit and so small, I'll probably have an insert made for it to lube my quarter bore bullets. That would be cute, huh?
Froggie