And suppliers?
Also, who owns these companies and what sort of profit turnover do they have?
Would I be right in guessing they all have at least tenuous military connections with their businesses?
How easy would it be for a new company to get into this line of money-making, ie, what sort of initial investment would you need?
I do not know who the biggest non-military arms manufacturers are but if you are interested in starting such a buisness the story of Ronnie Barrett might be instructive. http://en.wikipedia.org/wiki/Ronnie_Barrett He designed his rifles with civilian shooters in mind, but his work caught the eye of soldiers and now he has numerous military contracts. He was a successful photographer who got an idea for a new kind of rifle and he made that dream a reality.
Lockheed-Martin is usually the largest with Boeing close by. The order may flip-flop based on accounting steps and contract dates. Over $30 billion for Lockheed.
Others to check are Northrup-Grumman, General Dynamics, Alliant Techsystems, and BAE Systems, Inc. BAE Systems Inc is a subsidiary of the parent based in the UK.
Raytheon’s pretty huge too- I don’t know how much is “arms” per se, but they make a lot of sensors and radars and other stuff, as well as paveway laser guided bombs, HARM anti-radiation missiles and several other guided weapons.
See the o.p.'s request for “Non-military arms manufacturers.” (By this I assume he means manufacturers of weapons not primarily intended for sales to military organizations.)
For small arms I would guess that Sturm, Ruger & Company is high on the list, and very likely the biggest. Although Ruger has occasionally courted military organizations and submitted proposals or prototypes for competitions for military contracts, they’ve never made a significant sale to any military organization. (I don’t consider small sales of integrally silenced Mark IIs to SpecOps groups to count, especially since such sales were through a third party.) Most other extant arms manufacturers at least got a start selling weapons to militaries, even ones noted for large sales to law enforcement or private citizens (Smith & Wesson, Sig Sauer, Taurus). Virtually all the former East Bloc manufacturers produced weapons for military usage (private ownership of firearms being highly restricted in most East Bloc nations for obvious reasons) and most other manufacturers either produce low-end weapons (Raven Arms, Hi-Point) or customized or high-end weapons (Wilson, Sphinx).
Stranger
As for the initial investment, about the same as any other manufacturing enterprise; some high quality machine tools and operators, a design shop that knows how to make complex mechanisms, and a marketing and distribution organization. There is already a lot of competition out there and most buyers generally go with a known quantity. That being said, a few independent makers have survived (Charter Arms, Ithaca) and occasionally even thrived (Kahr) by focusing on an undeveloped area of the market like compact or concealable firearms.
Stranger