I read Corporate Download and saw that a lot of Ares runs are weapons field tests, and I'm sure that a lot of runs dealing with technological thievery are centered around the state of the art. Shouldn't runs like this have technological spillover, with products entering the market more quickly and becoming cheaper with the greater number of manufacturers entering the market? Like, if you field test the new model of sniper rifle and give a very detailed report, shouldn't it be on the streets in, like, a month or so?

Depends who you're giving that "detailed report" to, and what they think of it.

Possibly, possibly not.

First, it depends on a favorable, or unfavorable test.

Then, the test may be favorable, but they may be trying to get private contracts. Military/Lone Star/Other corps specializing in non-arms.

There are 1001 different reasons it would notbe out right away
Further testing
Closed contracts
Refinement


And 1001 reasons it would.
Espionage
Immediate release
Knock offs

It also depends on economics. Lets say the uberweapon you took out on a field test costs too much manufacture. Sure they have an uberweapon, but who is going to pay 40K a pop for one? They have to figure out how to reduce the manufacturing costs before they bring it to market.

Note for example, how some of the rifles chambered in 6.8mm SPC have been tested in teh field, but no one is mass producing them yet.

exactly. despite how it works in comics and movies, super-awesome advanced prototypes are really only worth something if they can be cheaply reproduced. having one of a thing is not going to make anyone any money--matter of fact, sinking lots of resources into creating a prototype that never goes into production is what you call losing money.

Also beware the GM in these situations. More often than not when I have a Corp using an outsider to test a prototype it is for one of 2 reasons: 1 to test the loyalty of the outsider for potential as a company man or 2 the prototype is such a lemon they don't want to risk their own personnel.

If the run gets a little too public the corp might hold off the release. For instance, if the runners also decided to "test" the sniper rifle on some random people/old enemies/tax collector, and the police now have ballistic evidence from a gun that's not yet in production.

What if it's a general field test, with the prototype being on loan for about a month while the shadowrunners use it?

there aren't many reasons a corp would want to do that. corps have their own personnel available for field-testing prototype equipment, without the added risk of the runner selling the prototype to the highest bidder.