favorite gun building tool

[Birddog6]

Norman Coot Knife Grinder. (72") Actually it is a 2" x 72" belt sander, but sold as a knife grinder.
That & a band saw, as I use Both almost every day.

[JTR]

My magna-visor!

[hudson]

Favorite tool Milling machine, most used tool 1 X 42 belt sander.

[WKevinD]

Spokeshave, rasp, scraper, in that order


Kevin

[Habu]

I'm with Whetrock: my pencils/sanding pad/kneadable eraser.  I re-draw every detail multiple times, start over, do it again. . .  and would hate to do that without a good sharp pencil.  Next would be my whetstone, because without it I'd never have tools with decent edges.

I've built guns and rifles without a decent vise (I used a hand screw C-clamped to my dorm-room desk to do a bench copy of a trade gun), with only a mill file and a 3-square files instead of the 40+ I have now, and with only a few chisels and gouges.  But I always start (and usually end) every project with my pencils and whetstone. 

[Monty59]

I don't build weapons, but I do repair sometimes antique ones, and my custom-built rifles sometimes need some work. My favorite tool is this screwdriver. Its short length makes it easy to control in your hand. It's easy to change between four different sizes, and it's specially shaped so it doesn't pop out of the screw so easily.

Monty

[P.Bigham]

Most used is my pattern makers vise.

[Kevin Houlihan]

My OptiVISORs.  I have them in 2 different strengths.

[oldtravler61]

  My shop table and light. Without them my work would look a lot worse..

[Berksrifle]

My first aid kit!

Ken

[mountainman]

I enjoy my egg beater drills, I use as much as I can, and whenever I can. There are some advantages over a battery drill believe or not. I can drill steel, brass, and wood of course.

[chuck-ia]

yes, I use mine a lot too. chuck

[thecapgunkid]

My heretical electric chisel.  You can tell whether or not it is right for the job when you plan the task at hand and I am too arthritic to whack away with a hammer.