Gunsmithing: Do It Yourself M1911A1 Inspection and Function Test (Part 4)

Gunsmithing: Do Your Own Inspection and Function Testing on the M1911A1 (Part 4)

To start with Part 1 of this series, click at Gunsmithing (Part 1).

By Steve Sieberts

As I outlined earlier in this series on the inspection and function testing of the 1911, I always look for previous efforts to gunsmith a firearm. And, as with any other firearm sporting previous work, some of these efforts will be blatantly evident, and some will be subtler. In Part 1, I suggested checking the magazine well for evidence of poor gunsmithing as an example of previous work that’s easy to spot. That being the case, let’s start Part IV with the assumption that the slide has been removed as we continue our inspection of the external areas of the firearm, looking at the more subtle aspects of functioning and inspection of the lower half of John Browning’s iconic design.

Once the slide is off, the next step is to remove the stocks from the pistol. As with most gunsmithing work, there is definitely a right way and a wrong way to do this. The first step is to make sure you are using screwdrivers of the correct width and thickness of the screw to be removed. Gunsmithing screwdrivers are “hollow ground.” In other words, the blade has parallel sides, torque is applied at the bottom of the slot, where the screw is strongest, and the blade fills the slot, none of which happens with most V-shaped screwdriver blades. This is important, as using regular screwdrivers on firearms will often ruin the stock screws.

Many shooters prefer to use Allen screws on their pistol stocks in order to avoid this problem, and they offer a bonus as they are distinctive and look great. Brownell’s has a great selection of stock screws in their catalogue, and I use them quite often in my 1911 pistols.

One trick I use when taking off the stock screws—or turning any screw on a firearm—is to support the screwdriver blade with the thumb to keep it from slipping out (See photo on page #TK). If you’ve ever let a screwdriver blade slip and accidentally scratched a $50 set of rosewood pistol stocks, you’ll know why I use this trick!

handgun assembly

In this fourth and final installment, the author gives plenty of pointers on the disassembly and inspection of the lower assembly.


Now that the stocks are off, I want to inspect the overall pistol for cracks and signs of previous work. One common modification to look for is previous attempts to tighten the slide to the frame. This is a very commonly requested modification.

Most people mistakenly believe that tightening the slide to the frame will result in greater accuracy, but as long as the barrel and sights are properly fitted to the slide, the frame has little bearing on the accuracy of a handheld pistol.

Where the modification really has an effect is on the functioning of the match pistol. 1911s that have the slide fitted to the frame will benefit from increased accuracy because the slide is moving back and forth in a consistent, repeatable fashion. Feeding is enhanced because the slide is moving forward, feeding the cartridge in a straight line. The same holds true with extraction and ejection, with the ejector and extractor in the same, repeatable position from shot to shot.

Look at the top of the frame for dents from a steel hammer. Normally, these would be removed with a draw file, but many amateur pistol smiths simply leave them there. If the frame rails have been lowered and the slide is still lose, measure how much material is left to see if the rails can be lowered any more. The maximum I recommend is about 0.110 inch. Anything beyond that and the rails will be too low and will probably crack if lowered further. I’ll show how to properly tighten the slide to frame fit in future articles on the Project 1911.

pistol smiths

A properly sized hollow ground screwdriver should always be used to remove the stocks from the pistol. Notice how the thumb supports the blade of the screwdriver bit in order to keep it from slipping.


When checking for cracks, the most important external areas to examine are the dust cover where it comes into contact with the frame and the slide stop pin hole. Remove the thumb safety by cocking the hammer, then wiggling the thumb safety while pulling it away from the frame. Make sure the plunger and spring assembly inside the plunger tube doesn’t come flying out. (You are wearing eye protection, right?) It should have a slight link in the spring to keep it from flying out. Check the plunger tube for looseness by squirting a little oil underneath it and trying to wiggle it. If the oil oozes out, the plunger tube will need to be re-staked. This is a really critical feature because if the plunger tube pulls away from the frame, it can tie up the thumb safety, which is not good if you need to use the gun in an emergency! Brownell’s carries a neat little plunger-tube-staking tool for this job.

At this point, ease the hammer down (never let the hammer fall on the frame without the slide in place), and push out the mainspring housing. Again, there is a tool specifically designed for this. Don’t use a punch, as it will mar the finish.

Next, remove the sear spring and check it to make sure it hasn’t been bent out of shape. Pistol smiths often make small adjustments to trigger pull, grip safety tension, etc., with the sear spring, but I’ve seen springs that were bent way too much. Most often, this occurs because the smith tried to overcompensate for a trigger pull that was too light or too heavy when the real issue was an incorrectly performed trigger job. (See photo on page #TK for a properly tensioned spring.) Before you move on, look at the rear of the spring to see if the hammer strut is rubbing on the spring, as this can affect the trigger pull.

Remove the hammer and sear pins. The parts of the hammer that I focus on are the hammer hooks. Again, look for previous work. The height of the hooks should not be below .010 by using the feeler gauge, and really, something between .012 and .013 is better. Check the hammer strut. This part should be staked to the hammer for best performance. If the strut pin is not staked and “walks,” it can cause trigger pulls to be inconsistent.

gunsmithing disconnector

Look at the facets of the disconnector: They should be sharp and flat.


The disconnector is a very critical part to the safety and functioning of the pistol. Make sure the dome has facets on it and isn’t worn smooth and rounded off. Look at the sear. The most important areas to look at are the primary and secondary sear surfaces on the nose of the sear. Normally, it should be about a 60/40 ratio—60-percent primary and 40-percent secondary—although a 50/50 ratio is very common, as well. Note: I will cover trigger work in much more depth in a later project.

Next, check the ejector. It should not protrude too far into the magazine well, and it should be tight. This is another area that should be checked for looseness in the same way as the plunger tube, front sight, etc. Put a little oil underneath and try to wiggle it to see if the oil oozes out. There are usually two types of pins to secure the ejector: solid pins and roll pins. If the pistol has a roll pin and you remove it, always replace it with a new roll pin. This goes for any roll pin in any firearm. Roll pins are not meant to be reused. Solid pins can be reused but can easily lose their ability to keep the ejector tight if removed and reinstalled too many times.

Next, take out the magazine catch by pushing it in and turning the locking latch counter-clockwise until the tension is released. Remove the mag catch and push out the trigger to the rear. Check the trigger to make sure the trigger pad is securely attached to the trigger stirrup. Check the stirrup for excessive bowing.

NOTE: This concludes a four-part series:

Part 1: The initial inspection and function testing of a new or used 1911A1 auto pistol.

Part 2: The inspection of the barrel and bushing assembly.

Part 3: The inspection of the slide and how the slide mates to the barrel frame assembly.

Part 4: This fourth and final installment covers the frame and its internal parts.

About the gunsmith: Steve Sieberts has been in the firearms industry for more than twenty years, and has certificates from five gunsmithing schools, eight factory armorer’s courses, and—perhaps most importantly—was the Chief Gunsmith for more than a decade at a classified Department of Defense facility involved in R&D, manufacturing and testing and evaluations of small arms for the military. A former member of the Army Marksmanship Unit, he has earned the Distinguished Pistol Shot Badge, President’s Hundred Tab, and is a member of the NRA 2600 Club. He shot IPSC for many years and currently competes in IDPA matches.

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