I'm looking to maybe machine an 80% AR lower. Now, I see that they have the fixture for doing this, BUT, I have access to a milling machine with a DRO. Is there anyone who has worked off just dimensions with no jig? If so, how did it go, and exactly where do you find the dimensions? The other thing I'm curious about is how have people marked them? Do they come marked Fire/Safe? BTW, Ares Armor is the company I'm interested in ordering from.