Matt 35750:
As it has been mentioned already, building a AR series rifle is worlds apart from building a 1911.
You CAN buy a kit--and get pretty lucky when most of the parts fit together without too much trouble. However, be well advised that the parts you get in most kits are of unknown quality. Some will be good steel--some might be not-so-good, some might be plain trash.
Like I said, you might get lucky. Or, you might not.
Here's my recommendation....
1. Obtain and study the Shop Manual on the 1911 pistol by Jerry Kuhnhausen. Read it from cover to cover--and then read it again. There is a wealth of information there.
2. You're going to need some decent tools, too. Sure--you can fit the thing together with the tools available from your local hardware store, but why not do it right?
3. ALWAYS remember the phrase: Buy quality ONCE, or buy cheap repeatedly. This is not to say that you can't good parts at a good price; but you will quickly find that the law of diminishing returns is in full force here. It does you no good to save $10.00 on a hammer if you have to buy two or three of them to get the gun to work.
4. Put down the Dremel, and back away SLOWLY.
Seriously, resolve that you'll put your first 1911 together without touching a Dremel tool. You can get into serious trouble with that thing.
I have been building and working on 1911 pistols now since early in my military career--starting about 1981. Here are the things I have learned the hard way about building and working on 1911 pistols.
a. Measure first. Then measure again. If you can, get someone to verify your measurements before you touch a tool.
b. Take your time, and go SLOWLY. When you get to the fitting, if there is any metal removal to be done, use what I call the 4/1 rule--for every 4 soft passes with a stone, measure once.
c. Get a sear and hammer jig. Really. Buy one and read the instructions.
d. Drop in parts usually don't.
e. Always cut on the cheapest part FIRST.
Good luck with your decision! If you want more info, PM me.