If any gun owner has a special area where they do any work, or maintenance, on the firearm(s) they own, they will soon find that a bench vise will be a great partner to help get whatever job is on the agenda done more quickly.
I didn't start out with the number of vises that now grace my shop benches, but only added each vise as I felt the need. When one firearm is mounted in my main vise, for example, and I need to do some adjustment when fitting a part for that particular firearm, it's really nice to have a separate vise handy to hold the part while adjustments are made:
The above is my main vise on #1 bench whereby I hold the firearm being worked on throughout the duration involved. This vise has a series of hardwood "false jaws" that are used for various barrel diameters and contours to keep the firearm rigid. Notice the thumb screws I added to remove any wobble that may be present in the vise. Rigid is GOOD!
On the right end of bench #1 is what I call my "Utility vise". I cut some aluminum angle iron to use as a form of protection for parts that I need to do some "hard fitting" on, while the main vise holds the firearm being worked on:
This is a vise, same as what Todd posted in his #18 post. Not an expensive vise, but its whole purpose is in having articulating jaws so odd shapes can be held fast in a position that makes working on the target part much easier, like butt stocks. The wood jaws in use on this vise have ¼ thick leather glued to the working faces and they grip parts most assuredly:
When working with a milling machine, it's most imperative that a sturdy vise be incorporated to do accurate work being held solidly while the metal cutting is taking place. If angles are involved, the Palmgren adjustable vise is a great helpmate to hold the part steady when cutting to that angle goal. It sure doesn't hurt to have a "digital angle finder" handy to register the angle for achievement: