Wild West Game Experiences

[VariousRen]

Hey everyone,

I'm currently working on a Wild West game, using premade characters and planned to last two sessions. The game is set during the gold rush of 1849 and I'm giving characters only guns that existed at that time period (ie. no cartridges, no repeating rifles, long reload times on everything, ect). There are no supernatural abilities, no meta game abilities (like luck), and combat skills for PC's range from 11 to 15.

This is my first game set in this time period, and I was wondering what some of the major differences between this and either a low tech or ultra tech game that I should be looking out for? In particular:

1. If the players get into combat how far should I be planning on having combat take place at (rifles have a 1/2D range of ~100 yards)?
   
2. How worried should I be about a single lucky shot putting a PC out of action for the entire campaign (it will take place over a few weeks of traveling in game)?
   
3. Are there any extra rules scattered through Martial Arts, High Tech, ect that are ideal for a game like this?
   
4. Anything else to be aware of from your experience?

If all goes well with this game I'm planning on making it one of my go-to introductions to GURPS, so I want to make sure I'm as prepared as possible.