The Engineer update went live last night, and the most powerful item it adds is the Wrangler. It makes your Sentry twice as powerful, three times as tough, gives it infinite range, and lets you tell it where to shoot. Unfortunately, though, it requires 17 achievements to unlock, and there are only about 10 easy ones. Luckily, there's a shortcut to get this electro-bastard in just an hour of play. Here's what you need:
You will lose the Frontier Justice in the process, but it's not the most exciting item, and you're likely to find it again sooner than you earn the 17 achievements it'd normally take to get the Wrangler.
Here's what you do:
There's only one possible outcome for this craft: the Wrangler. No risk involved. And unless you burned through your stock trying for a Golden Wrench this week, you should have all this junk and more lying around in your inventory.
If you haven't found the Frontier Justice again by the time you get the 17 achievements it'd normally take to get the Wrangler, no sweat: just use this method with your spare Wrangler to get the shotgun back.