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Discussion Starter · #1 · (Edited)
After a long discussion in a thread, I received a PM from a moderator requesting I write this up for this section. So here goes…

The most common stoppages or malfunctions I see with 1911 pistols are all too commonly and often mistakenly called, "failures to feed" or FTFs (sometimes I wonder if the poster means "failure to fire"-another form of malfunction). Not that "failures to feed" never occur because they can and do. But that the most common issues with all the Kimbers I have observed or dealt with are actually "failure to chamber" and "failure to return to battery" (or lock).

So what is Feeding?

There are eight steps in the cycle of operation. Assuming the weapon is loaded and cocked at the onset, these steps are: Firing, Unlocking, Extracting, Ejecting, Cocking, Feeding, Chambering and Locking. Knowing these will help you narrow down the possibilities of what the problem may be if you can determine at what step in the cycle of operation the problem occurs.

Since "failures to feed" are what many throw out there as the issue, what is it? When does it start? And when does it end?

Feeding is the process of the disconnector rail of the slide moving forward and pushing the top round in the magazine up the feed ramp and "presenting" it to the chamber for chambering. There are a lot of little steps involved in the controlled feeding process of the 1911 but to simplify things; if the bullet has begun its entry into the chamber and the cartridge is no longer under the control of the magazine's feed lips-feeding is over. If the slide fails to move the round from the magazine; the round "nose dives" into the front of the magazine or crashes into and stops against the feed ramp; or stands up like a stovepipe trapped between the barrel hood and breech face-those are feeding issues and another discussion.

Failure to Chamber

Failures to chamber generally occur because the base of the cartridge is unable to continue its rise up the breech face to its necessary position of being in-line with the bore. The rim will have begun its entry into the gap created between the breech face and claw of the extractor. If the gap is too insufficient, the case will stop as soon as contact with the extractor is made. In most cases the rim will enter and stop at some point prior to the base lying flat against the breech face.

This stoppage can also be caused by a burr or damaged breech face that prevents the cartridge base from sliding upward. But all too often, the extractor is the cause. In regards to the breech face people often refer to polishing it. Caution should be used here in that it does not need to be a glass or mirror finish. It just needs to be smooth and void of burrs. But know that it is not perpendicular and overzealous polishing can change the angle and possibly headspace. The firing pin port is preferred to be chamfered.

In regards to the extractor most production guns I have checked, have insufficient gap between the breech face and the inner surface of the claw. In addition, there needs to be sufficient bevel and radius at the bottom (entry point for the rim) of the extractor; sufficient engagement on the rim and tension to hold the once fired empty case flat against the breech face by pushing or pinning it against the guide block on the ejector side of the breech face; so it is in position for the ejector as the slide travels to the rear.

In addition the extractor is to be held firmly into position due to its fit with the firing pin stop. How the FPS interfaces with the extractor is what will prevent the extractor from "clocking" or slightly rotating back and forth its channel. A clocking effect obviously will change the angle and amount of engagement of the claw with the rim of the case. Clocking can lead to inconsistent ejection patterns. The FPS also should prevent the extractor from fore and aft movement in its channel.

So you may ask why does your gun run Brand X ammo fine but Brand Y causes this stoppage?

I have found that there are great variances in the rim thicknesses of various makers of .45 ACP brass. If the extractor gap is too small for the ammo you are running…a stoppage! I have seen pistols run our duty round (premium and expensive) all day long with no issue. Feed it a lesser cost or ball ammo even from the same maker and …a stoppage. I cannot prove it but it seems that the brass that does not meet spec for the top end line is deemed a "seconds" and sent to be loaded as the lower grade practice ammo. Nickel plated brass will tend to cause less problems due to it being harder and less prone to the metal extractor edges biting into it and stopping its progress through the process.

Obviously rims get damaged over time when brass is reloaded over and over. Burrs on the inner surface of the rim or displaced metal in the extractor groove can create this issue when that damage aligns with the extractor. When shooting with others and picking up brass at the end of the day you may be getting brass fired from another's pistol. If his extractor is poorly fit I call it a "brass butcher" as his gun may be running but it is chewing the brass to hell.

Damaged rims and displaced metal on new brass can be a strong indicator of an extractor that needs tuning-even if the gun has been running fine. Seeing this may result in stoppages if the brand of ammo is changed.

Failure to Return to Battery/Lock

Failure to lock is when the case is fully under the extractor, flat on the breech face and the cartridge is in line with the bore and usually about 90%or better fully in the chamber. For some the advice or solution is to change to a different brand of ammo and or put in a new recoil spring and or one of a greater strength. But that is wrong if the ammo is within SAAMI specs. What it is, is that the leade of the chamber is short (or non existent) and the ogive of the bullet is engaging the rifling too soon and prevents the gun from a complete chambering process preventing it from locking. A stronger recoil spring will only drive the slide forward faster thus driving bullet's ogive into the rifling so hard that the bullet overcomes the crimp and is pushed back into the case enough to completely chamber and lock. In the case of a 5" 1911, standard spring is 16# for standard power factor ammunition. But it does not take 16# of stored energy to complete feeding, chambering and locking if the parts are fitted correctly. A 12# spring should do it…even a 10# spring like found in the Colt Gold Cup (made for light target rounds).

Two cartridges can be of the same overall length but one will present this issue. That is because the distance from the base to the ogive is longer than the other. Projectile dimensions vary and the tolerances can vary a couple of thousandths of rounds in the same box. That is why you may only see this stoppage one in a while and blame it on a dirty gun etc. Though with no leade to act as a transition of the chamber's rim to the rifling; jacket material or lead will be shaved off and build up making the rounds more difficult to seat fully the more you shoot.

The gun should run with all SAAMI spec ammo and the leade should accommodate it.

So what is the corrective action? Finish reaming and throating. Depending on the reamer it may cut the leade or a separate throating reamer is needed. I have never found a Kimber chamber that a Manson finish reamer did not remove some metal from the chamber and or leade. Running a finish reamer in the chamber then polishing ensures the chamber is correctly dimensioned and eliminates it as a possible cause for failures to extract, should those stoppages ever arise.

Personally, I do not believe in "break in" periods. Nor do I believe a general purpose/defense gun should be so dependent on a special load to ensure operation. I understand that production guns usually need some attention to improve their performance. When I get a new one, I go through it and address issues such as these before going the range. Regardless of brand and whether it is running (today) or not; someone with some knowledge will find issues that should be addressed to avoid future problems and frustration.

Here is the thread that started this. In this thread is a non scientific test to see if the leade is short for the ammo you are using.

http://www.kimbertalk.com/forums/kimber-1911-forum/1735-scp-hd-range-report.html
 
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