A German made Erma-Werke Model EG 712 .22 rimfire lever action rifle made its way to my shop in the hands of a happy return customer. I had never seen or heard of an Erma-Werke but this gun looked familiar. After some research, I realized it is the same design (predecessor) as the Henry .22 caliber Lever Action Rifle.
Since the customer’s gun has been and gone and I needed a few additional photos for the illustration purposes of this article, I borrowed a friend’s Henry .22. I thought I would point this out now in case you wonder why there’s a nice new gun in the photos instead of the customer’s old, worn gun.
First thing the customer and I did was prove to each other the gun was clear and safe, then we got to talking. The customer wanted the gun given a detailed strip and clean. More important, the customer had a problem he wanted fixed. The empty cases were failing to extract after every shot and had to be removed from the chamber by hand.
When others shot the gun, they were unaware the fired cases were still in the chamber. After shooting the rifle and cycling the action, they naturally found the lever wouldn’t close. The natural tendency was to exert more force on the lever to try and get it to close. Don’t laugh, how many times have all of us tried to fire rifle or shotgun with the safety on when the game showed up or the clay pigeons flew? If we’re honest, the answer is all of us . . . at least those of us who use the safety as we should.
In short, fired empty cases would not extract from the chamber which caused the next cartridge feeding to cram into the empty case stuck in the chamber. This resulted in deformed cartridges, rendering the gun no fun at all to shoot. The customer thought the gun would need a new part which Henry calls a “Carrier,” but I tend to call a “Feed Guide.”
I explained to the customer why it really needed fixing. Enough force exerted on the lever could crush cartridge rims to the point of igniting the priming compound. Fortunately, the problem had not caused this to happen yet.
Being an AGI student, I understand this type of malfunction usually revolves around one or two problem areas: the chamber and/or the primary extractor. These two areas are the focus of this article. For the clarification of some terminology throughout this article I put together the two photos below titled: “What’s What:”
The first area I inspected was the chamber. First check was for any firing pin damage to the chamber mouth. Reason being, in a rimfire gun the firing pin is positioned in line to strike the rim of the cartridge case because this is where the priming compound is.
This also puts the firing pin in line with the edge of the chamber. If a firing pin protrudes too far, for whatever reason, and the gun is dry-fired, the pin can contact the edge of the chamber. This can damage the chamber by raising a burr in the chamber mouth.
This burr can make cartridges difficult or impossible to feed and extract. When a cartridge is fired the pressure causes the brass case to expand, so if there is a burr the brass can mold around it. For this reason it is a good idea to avoid dry-firing a rimfire gun. I own a rimfire with such damage to the chamber and have included the picture below to illustrate it.
The Erma-Werke has a firing pin dent above the chamber on the barrel. Fortunately the lower portion of the firing pin, that portion of the pin in line with the edge of the chamber, doesn’t protrude far enough to contact the edge of the chamber, thus the chamber was undamaged.
The reason why the firing pin dent in the barrel occurred is the upper portion of the pin is too long and the gun had been dry-fired. To explain this, when the action is closed and ready to fire the top portion of the bolt body is resting against the upper end of the barrel. When the hammer struck the rear of the firing pin, the tip of the pin was able to protrude past the bolt body (positive protrusion) and contact the rear of the barrel just above the upper edge of the chamber.
From my measurements, if the lower portion of the firing pin, that portion of pin in line with the edge of the chamber, was .003″ longer and the rifle was dry-fired, the pin would begin to contact the edge of the chamber. Any more than .003″ pin protrusion from the length it already is means damage to the chamber is going to happen.
Rimfire firing pin protrusion is definitely something to be aware of, and there’s more to it, and I will discuss the correction of this gun’s problem and the Henry setup later in this article. Now I would like to return focus to the culprits of the gun’s failure to extract. Next, I checked the chamber walls for roughness. If the chamber is rough from rust pits, factory machining marks, debris, etc., the expanded brass will cling to them more than smooth ones. Rough walls make it difficult or impossible for the primary extractor to pull the fired case from the chamber.
Here’s how to quickly and easily check if the chamber walls are rough or smooth: With the muzzle pointed vertical to the ground, drop a new, unfired cartridge into the chamber mouth. If the cartridge fully enters the chamber on its own, the chamber is good and smooth. If the cartridge doesn’t fully enter on its own, the chamber is rough and should receive a light polishing. Of course an oversized chamber would allow them to just fall in, but the lack of accuracy and bulged cases would be a give away.
In the customer’s gun the cartridge would not enter completely on its own, it stopped about half way in. To get it to fully seat, I had to press it in. When I pulled the cartridge out of the chamber with my fingers, I realized how difficult it would be for the primary extractor do this on its own.
I was not surprised the chamber was rough in this gun based on the overall lack of cleaning. The rifling looked “melted” from being heavily leaded, worn out, or both, so I cleaned the bore and the chamber. After a thorough cleaning the bore was shiny, the rifling looked sharp and some debris (a bit of rust and powder residue) was cleaned out of the chamber. I checked for chamber roughness/smoothness (as explained above) but it was still too rough for cartridges to slip-seat into it. The chamber is rough and needed polishing.
To be continued . . . .