Gunsmithing: Do It Yourself M1911A1 Inspection and Function Test (Part 3)

Gunsmithing: Do Your Own Inspection and Function Testing on the M1911A1 (Part 3)

To start with Part 1 of this series, click HERE.

By Steve Sieberts

Column two in this four-part series covered the inspection of the barrel and bushing assembly. In this installment, we’ll focus on the slide and its internal parts, and we’ll tie everything together in the final installment.

When inspecting the slide assembly, always look for previous work. If the slide has been squeezed by previous pistolsmiths in order to be “accurized,” then you should look for areas around the thumb safety notch for cracks. You can also tell if the slide has been squeezed if the slide rails have a “pinched” look. A quick check from the rear of the slide can confirm this.

Having previous accurizing work won’t necessarily cause me to reject a pistol, but I’d use it as a reason to really look hard to see if the work was done professionally, and what other work was completed on the pistol. If someone is trying to sell you a gun that they claim has never been modified, then knowing what to look for as far as these types of modifications go will help prevent you from buying a pistol that’s unserviceable and potentially unsafe.

Gun Repair

In this installment, the author covers the inspection and disassembly of the 1911’s slide.


One good check to do is the barrel/slide/bushing fit. If you’re inspecting a service-type pistol or an unmodified factory commercial Government Model, then tolerances in the barrel/slide/busing relationship will be very loose. “Finger tight” is the rule on the bushing. The barrel should be able to be pushed up into the locked position and fall in and out of battery freely. Also make sure the front sight tenon is not rubbing on the bushing.

On a Match pistol, these tolerances are much tighter. The barrel, as I pointed out in last month’s issue, will be tight between the barrel hood and the slide, with very little to no daylight showing around the barrel hood. You should be able to push the barrel up into battery into the slide, and the barrel should be locked into battery and not fall out of battery by its own weight.

Additionally, if you push the barrel up into battery and it springs back at all, then the barrel and barrel bushing is too tight and will need to be relieved so that the rear of the barrel can pivot upward during lockup.

Getting back to slide inspection, one good area to look for previous modifications that are sometimes hard to spot is the ejection port. Lowering—and sometimes lowering and flaring—the ejection port is a common modification on the 1911 pistol. This is done in order to make it easier for the fired case to clear the ejection port when the slide retracts during the ejection cycle. Gunsmithing problems can occur when a pistolsmith lowers the port too much, weakening the area.

I make it a point not to lower the port more than about .460 from the bottom edge of the slide rail. (See photo below) this will leave enough of the web of the slide to ensure it won’t crack, but will lower it far enough to make it easy for any fired case to clear. Also, look to see if the work was done on a milling machine or by hand. While I have seen this modification performed by hand with good results, it takes a long time to do it this way correctly, and poor work is very easy to spot. Performed on a milling machine, however, this job is very easy, looks nice and is a useful modification.

Gun Repair

Check to make sure the ejection port is not lowered too much. In Siebert’s opinion, anything below .450 is too thin.


The next area to look for is the extractor, one of the most abused parts on a 1911 pistol. When the pistol fails to feed or extract, the extractor is usually the first place a gunsmith looks. The extractor needs to have the proper tension in order to function correctly, and has to be fitted properly for best functioning. Sometimes this part can be installed as-is and function very well. Unfortunately, some gunsmiths will try to “adjust” the extractor tension when the feeding issues are really being caused by something else.

Failing to properly diagnose a malfunction is a common reason why many parts like the extractor, barrel and frame feed ramp are modified to the point that they are unserviceable or unsafe. If the gun won’t function properly and you suspect it’s the extractor tension, here’s the best way to check.


CAREFULLY pry out the extractor.

Take a dummy cartridge and, with the slide off the frame, slide the dummy cartridge under the extractor and hold it against the breech face. Let go of the case and rotate the slide and see if the extractor holds the cartridge in place. If it falls out, the extractor is a little bit too loose, if it’s hard sliding the dummy round under the extractor, then it’s probably a little too tight. It’s one of those areas of pistolsmithing that you just have to get a feel for what the proper tension is through experience. Look to see if the edge of the extractor is biting into the side of the case. Take a look at some of the fired cartridges (if you have them) and check for extractor marks on the extractor groove of the case. Note: When I get into building our “Project 1911” in a future issue, I will cover extractor fitting more in depth.

test for proper extractor tension

A good test for proper extractor tension is to see if it holds a dummy cartridge in place against the breech face without falling out. I usually rotate the slide 360 when performing this test.

To remove the extractor, you first have to remove the firing pin and spring. Inspect the firing pin stop to make sure it’s not overhanging the disconnector timing track. It should be as flush as possible. If it’s not flush, it will put excessive wear on the cocking pad of the hammer.

To remove the firing pin, push in the firing pin with a drift punch or similar tool and simultaneously dropping the firing pin stop slightly. Brownells makes a nifty tool for removing the firing pin stop. The firing pin is under spring pressure, so make sure you have it covered while you slide the stop out all the way, and then ease out the firing pin and its attached spring. The spring should be attached to the firing pin. Gently pry out the extractor by using a small screwdriver blade to get underneath the notch. Be careful because it’s easy to slip and gouge the finish of the slide.

Once you have the extractor out, examine it. It should have a slight curve to the left from the middle pad forward. If the extractor was a little loose and wasn’t able to hold in a dummy cartridge, you can tighten and loosen tension by slightly bending the extractor either toward the cartridge case or away.


Another critical area of the pistol to inspect is the breech face and firing pin hole. Remember, headspace on any firearm is defined by the distance between the breech face and the portion of the chamber that stops the forward movement of the cartridge. In the case of the .45 ACP, it’s the distance between the breech face and the shoulder of the chamber where the cartridge case mouth makes contact. So, this means that you want to be very careful about polishing the breech face, because any removal of metal from the breech face could increase the headspace dimension and result in a very unsafe firearm. Look at the breech face and see if there has been any attempt to polish out tool marks. If there is, I would seriously consider replacing the slide.

removing the firing pin

To remove the firing pin, depress the firing pin and slightly slide out the firing pin stop.

The same thing applies with the firing pin hole. While it’s possible to safely remove burrs from a damaged firing pin, it can be very dangerous and unsafe if the hole has been drilled out or enlarged, since an enlarged firing pin hole will allow a primer cup to flow back into the hole when the pistol is fired. Not a very safe situation. I’ve seen firing pin holes that were damaged by gunsmiths attempting to deburr the hole. They went overboard and damaged the slide. Remember, a little polishing goes a long way. It’s always easier to remove metal than it is to put it back on, so be careful.

Two specific areas to check for cracks on the slide are right behind the recoil spring guide tunnel, and between the breech face and the extractor hole. (See photos) I have seen cracks in these areas and the pistols have still shot many thousands of rounds in this condition, but it’s still something to be aware of.

The final column in this four-part series on function testing, inspection and disassembly of the 1911 will be on the lower receiver and its internal parts. Stay Tuned!

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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