For our home MS prefix Mil Spec plug builders out here reading all this:
Remember, aircraft connectors (also called "cannon plugs") require a special 3 point indexing crimp tool to connect the pins and sockets to the individual wire leads unless you are going to solder each pin. The crimp tool is EXPENSIVE!!!!!!
Also, most plug and socket items only come with the exact number of pins. I don't know why, it just is. Over crimp, bend or break a pin during insertion or during removal and you are kind of messed up.
Removal/insertion of an individual pin from the rubber shell center also requires special insertion and removal tools. This is because each individual little pin is held in place by a compression spring or O clamp. Bust 1 pin compressor and the entire plug is no good. Also insertion tools are either front or rear use depending on the plug. A front insertion/removal tool can not be used on a rear insertion/removal pin set up. 1 cheap plastic Insertion/Removal tool usually comes with a plug and pin assembly but they don't last very long and break easy if you are not gentle with them.
When inserting the pins, be careful to guide them correctly. Offset a pin in the it's rubber plug isolator hole and it will come out at the other end at a different hole area and then the rubber isolator/locator is shot and the entire plug is shot.
When cutting and trimming the wires to prep them for pin crimping, care has to be given to the length of each conductor. A conductor in the center of the plug will be a different overall length than one on the outside row or ring. If a wire is too long, it will push the pin right through the plug when you assemble the backshell... too short and it will pull out.
About those backshell clamps while we are on it... make sure you put that Devil's spawn child on the wire BEFORE you start inserting the pins in the plug isolator. If you don't you have to de-pin the entire plug. Not a fun thing. Take that bit of advise from someone who built a 192 pin and figured it out at the end of pinning. 2 days of work wiped out for nothing.
During assembly, if you insert a pin in the wrong locator hole, EVERY wire thereafter will be wrong. Identifying which wire goes in locator position capital a ("A") is an utmost requirement. Become familiar with pin locator markings... Pin #1 will always be "A" (Capital letter A) and goes to Capital Z. Then it starts at lower case 'a" to lower case "z". Once again... I'm guilty as charged. Heh heh. also remember the letters "I" and "O" are not used.
http://www.dmctools.com/default.html Daniels Manufacturing Company has a lot of information about our plugs and how to assemble and disassemble.
I have a lot of experience with cannon plugs up to and including the 292+ pin plugs (pure hellish nightmare). It was my specialty during my shipyard days and I've destroyed my fair share of them.
Hope this doesn't scare anyone away from building their own plugs but instead helps out a little.
All the best-
Dave