Cooey model 75 Shell Jamming

T

TacticalCanuck

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hi CGN,

Have an old model 75 that loads and fires just fine, quite accurately too. Issue is, the shell is jamming up pretty good in the breech after the shot and not extracting. Any suggestions? The same bolt extracts shells just fine from another model 75, so it's not the extractor. I have completely cleaned the breech very very well, thinking residue and powder had simply built up, but this isn't the case.

Any suggestions on how to better diagnose the issue? Treating it will be part 2 if the problem discovered has a fix.
 
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Possibly a bit of a rough spot or rust or pitting in the chamber. Also, make sure to clean out the recess that the extractor fits into when the bolt is closed. Another possibility is a bulged chamber.

What do the empties look like? Are there any scratches down the length of them from rim to mouth? Does the rifle extract LIVE rounds?

Another thing is the chamber where the firing pin hits. If some .22 rimfire rifles are dry fired, the impact of the firing pin tends to put a bit of a burr on the edge of the chamber.
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Thanks Buffdog, I'll try to get it out tonight and fire a couple, and take pics of the shells should they have marks. The gun is old, and I've had it only for a short while, I got it, cleaned it up and intended to for it and a 2nd '75 to be 2 learner guns for the kids. So, dry fired, I haven't dry fired it, but I will certainly take a much closer inspection of the chamber and area. There is a mild bit of pitting in there, about 1/3 the way in.

When I acquired it, I only put some cci shorts down the pipe, and they worked fine, so the clean up process was started after that. I figured the shorts left residue when an empty shell was tested. Maybe I just need to get some shots down it to work it in. Maybe I can only use shorts.

I wonder if I took some sand paper on a dowel and tried to smooth it out a little.
 
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Do not get too drastic yet. Sandpaper on a wood dowel is not the best idea. Sandpaper will scratch the chamber walls. If that is the route you go, then very fine 600 followed by 800 emery paper is better. The problem with a wood dowel is that you can end up with an egg shaped chamber, especially if power is used to rotate the dowel.

I assume you are having problems with .22 Long Rifle ammo, as you state in your second post that you fired it with .22 Shorts and they worked and extracted all right. Most older .22 barrels were made of a mild carbon steel and they worked fine because of the lower pressures and velocities of that cartridge. However, if a rifle was used with a LOT of .22 Short ammunition, it is possible that the front end of the chamber could be eroded, and a fired .22 Long Rifle case could hang up when it expanded into this eroded area.

It is also possible that the "pitting" that you see is a stubborn lead deposit from the shorts, or baked on crud from firing the shorts. I would first use a good bristle brush on that area along with a good solvent or cleaner and see what you get. Do not use a drill or power on the brush, but do it by hand only.

The Cooey 75 is a relatively simple rifle. If the chamber is worn too much, it would be a fairly easy job to cut about an inch off the barrel, and rechamber it after turning it down to fit the receiver. Any competent gunsmith should be able to do this, BUT, the cost may be as much as what the rifle cost you in the first place.

If you decide you have to polish the chamber, the key word is POLISH and not remove much metal. Do not run your dowel in too far as it will enter the throat and rifling. It would also be good if you could turn down a wood plug, with a hole through the center to hold the dowel. This should fit into the rear end of the receiver, and act as a guide for the dowel to keep it aligned with the chamber.

Anyways, fire a few Long Rifle cartridges, and inspect the cases for scratcfhes or a "blown out or expanded" small spot near the mouth of the case. Then, go from there.

If the chamber is peened from dry firing, that is another different fix that is needed.
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Turns out the breech is pooched. The rim on the cartridge is supposed to sit flush but a small portion of the metal is gone revealing the brass. I do not think it's safe. Thanks for the thoughtful replies buffdog!
 
Well, the barrel could be set back - but the expense would probably exceed the value of the rifle.
 
I wouldn't bother having set back I've not had this long and it's a shame though as I got it on the EE. Model 75 are common I'm sure I can find another. If they can't share I will break out the little badger :)
 
It seems as though you were laded with and sold someone else's problem.
Pity someone would off load such an affordable pass me down plinkster.
Sorry for your grief.
I'd sure be brilliant if some gunsmith sort would take to accept such a monument,
cure the ailment and offer it up to a shooting facility that promoted shooting
for those inclined, but lacking the resources for such a fine specimen.

Yes..................I'm 100% serious.
 
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