AR-15 and AR-308
To build an AR-308 or AR-15 out of an 80% lower receiver, you are going to need an Armorer’s Tool to effectively tighten down the castle nut. There is no need to go with the most expensive option. All you need to do is find the one that works for your price range and does the job you need it to do. The TAPCO multi-tool is solid, but if you’re looking at building an upper receiver yourself, you’re going to need the Magpul Armorer’s wrench.
After you have acquired an Armorer’s Wrench or Armorer’s Tool, you’re probably going to be fine with the tool set you have. However, getting a punch set can make life much easier when installing the bolt catch roll pin and the trigger guard roll pin if you are using a traditional mil-spec AR-15 80% lower. Because our lowers feature a milled in trigger guard, customers do not have to deal with that part of the installation at all.
When it comes to the M1911 frame, there is quite a lot more work involved than there is when building an AR variant.
For the M1911 it is essential for you to get a Plunger Tube Staking Tool, which can be found in the link below.
We recommend that you pick up a bench block tool. These can be helpful for holding the lower or frame above a flat work surface, yet it still allows pins to be hammered out and captured. This means, conveniently, that you won’t lose them.
Punch sets, like the ones listed above in the AR-15/AR-308 section, help for getting a pin or two hammered in properly to the frame. No other specialized tools will be required.
For fitting the slide to the frame, you may want to get some lapping compound, one in 300 to 320 grit and the other in 600 grit. This ensures that as you work the slide back and forth on the frame rails there won’t be any friction on the finished product.
To use the lapping compound, first apply a thin layer to the frame's rails and then work the slide back and forth. You will want to use the 300 to 320 grit for the first series of passes and once it feels relatively smooth, clean it off with some water and a rag. Next, you will apply the 600 grit, and move the slide back and forth until it feels buttery smooth with the frame. Make sure to clean it off again afterwards.
If your slide moves back and forth freely without applying the lapping compound, there is no need to use it, and sometimes this will happen and you'll get lucky. Make sure to fire a healthy amount of ammo through the gun to fully break it in as M1911's are known to be a bit finicky from time to time.
Polymer 80 PF940C Tools
If you have a basic Punch Set (like those listed in the AR-15/AR-308 section) and a Bench Block (as listed in the M1911 tool section) you have everything you need for this project, but you may find a set of needle nose pliers helps with the magazine spring installation. It is very easy, likely the easiest off all builds we support.
Basic Bench Block - https://www.midwayusa.com/product/272269/lyman-x-block-gunsmith-bench-block