My first post! I have been trying various DE safety razors as I can get a hold of them and recently a friend gave me an old army issue khaki set containing the army issue Gillette ball end razor. The serial number is J 358. That is an unusually low number isn’t it? The handle has a crack and the case is quite worn and missing one thumb tack, but the razor head looks pretty good. I tried it out and was amazed how mild it is. Efficient, but mild. I had read that the old ball end open comb razors can be agressive and/or tricky to angle correctly but this one seems almost foolproof. I find it very smooth and precise and definitely my favorite razor thus far. Did the army issue ball end razors change any as the production ramped up?
Welcome to TSD @Hhhhiii! Great first post and I don't have the answers, but give it a few minutes or a couple days. The answers will come since we have many resident experts and well informed members. Feel free to post photos. If you have any other questions, stop by the Welcome Center and make an introduction post. The gang will be glad to greet you.
Can't answer your questions but I have that same razor, minus whatever set it came in, and agree with your findings: it's not particularly aggressive but it is very efficient. Welcome aboard.