Prototypes

That depends on your criteria for "correct". Functional can be very different from what a product needs to be in order to be marketable. Product design is dependant on enough diligence in determining all the product requirements. Many times this can not be defined without an element of trial and error, prototypes are almost never finished designs. Usually the first couple of production runs is where the final changes that finish the design take place. The benefit of rapid prototyping, CAD, and the other prototyping resources is that they help speed up the trial and error process and let the prototypes get a little closer to looking like finished designs before the commitment to the tooling required for the finished design takes place.

Both good points:

As a Solidworks designer I can imagine in a few more years not only will you be able to design new products but run a market analysis and get suggestions for improvements directly from the software itself.

The way CNC machine design is going even a single person shop will be able to produce new designs from his/her garage with a small investment to produce to order the ultimate lean mfg. I even see a trend for using drop ship mfg coming as machinery gets cheaper and small scale manufacturers get involved through the websites of the CAD developers.

Don't bet on it!

I remember hearing about the silencer that S & W made for their M-76 submachine gun back in the 70's. Worked well, until they send it down to the Special Warfare Center at Ft Bragg, where a group of South American commandos were firing the weapons, cleaned them that evening, and had the silencers blow up the next day!

Seems that S & W used sintered porous copper spacers for heat supressing elements, which worked fine--until the S.A. troops cleaned the SMG's by washing then in a drum of #2 diesel fuel!

In the morning, the porous copper was soaked with fuel, and on the first shot fired--yep, you got it!

The U.S. Patent # is 3,713,362, and it was #30 that let go with a bang, to say the least!

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=3713362.PN.&OS=PN/3713362&RS=PN/3713362

Allen

So would you consider that a poor design or a poor cleaning method? In my mind a weapon which needs cleaning fluids and lubricants which might not be available in the field when you count on the weapon the most is just ignorant design at best.

Since you will need to clean and maintain the weapon in the desert or the jungle in the arctic etc the cleaning method should be purely mechanical and the lubrication intrinsic to the design.