I need help with a cooey 840!

S

Skaal-tel

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G'day gents,

I have a cooey 840 that was my dad's first shotgun. It has seen a long and interesting life.

The problem is that it breaks open on its own after a shot is fired.

The barrel is tight to the action when held in the hand. With the barrel closed it can not be pulled forward, or side to side. The wooden forend was a bit loose, and I believe it has the wrong forend on it.. but I've tightened up the spring a bit and it is now nice and tight.

I have two places with some wear that I need an opinion on. The pin in the front is slightly worn on the side facing the shooter, where the barrel rotates on. Also, the part of the (unsure of the term) barrel lock/extractor thing? the release catches on isn't a perfect V shape, the lower part of the V has some wear on it.

Is there a member here with some experience fixing these? I can drive out the pin and rotate the fresh side around to the rear, and I could have the "V" notch welded up and ground down to shape. I'm not sure if either will help the problem, so I'm asking here!

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I'd like to fix it up just because I can. Before someone tells me I can buy another one for less than the cost of repairing it..
 
There are a few things to check before swapping parts out. If you have some Dye-chem (or magic marker), place some in the "V" notch and carefully reassemble the shotgun and close it. Open it again and note how much of the "ink" is gone and post a pic of that. It almost sounds like there is not enough protrusion of the barrel lock into the notch. Taking the buttstock off, is there any rust or gunk preventing the parts from moving freely?
Do you know if the barrel is original to the shotgun? I ask that because you claim that the forend may not be correct.
 
I do not know if the barrel is original. I believe that it is, but can't say for certain.

The action parts seem to move just fine. Oiled thoroughly. I will certainly check for the complete engagement. Just judging by the polish of the movement in the notch I would say that it does not seem to bottom out in the V. I'll get a pic up tomorrow.

I'm not that far north zuke :)
 
Alright, I apologize if some photos are slightly fuzzy - I am still practicing with the camera and it is a fairly dark basement!
IMGP2944_zps96953497.jpg

Serial numbers match. Barrel is gorgeous - inside is a mirror.
You can see the rounded bottom edge of the notch in this photo.

Here's a picture of the receiver. The pin is still round although polished. I haven't got a micrometer to measure out of round yet but it isn't visually noticeable at any rate.
IMGP2945_zps7501df17.jpg


mating surface of the barrel.
IMGP2946_zps20c6299c.jpg


I sharpied up the notch and worked the break a few times.
IMGP2948_zpsf13a9d41.jpg

wiped the left side clean on the first try, 3/4 of the way up. There is light imprint over the entire surface all the way across and 3/4 of the way up.

The catch noticeably moves to one side and then down when operated. I don't know if that's relevant to the breaking open after firing.
 
Are you saying that the catch (or top snap lever) moves only to one side and noticeably moves up and down in the top tang? If so, take the buttstock off and check the internals of the action. Post a clear photo if possible.
Judging by the colour of the V-notch, you have minimal engagement.
 
gunrunner100 said:
Are you saying that the catch (or top snap lever) moves only to one side and noticeably moves up and down in the top tang? If so, take the buttstock off and check the internals of the action. Post a clear photo if possible.
Judging by the colour of the V-notch, you have minimal engagement.
Click to expand...

No, the lever is fine. The (I wish I had an exploded diagram to refer to) piece which engages the notch in the barrel and is moved when you operate the lever scrubs sideways 1/8" then moves downwards.

It's pictured in the second photo underneath the firing pin.
 
That would explain the ink missing from the one side of the notch. Still would be interesting for you to take the buttstock off. The top snap is a "pot metal" and is prone to wear from use. This would affect the barrel lock slightly.
 
First, go back a couple of weeks in this Forum and review the posting "Loose butt stock on Cooey 840" where Lyle700 had a similar problem with his gun opening after being fired. I advised him how to tighten it up a bit. The locking wedge that goes into the notch should move down and back when you push the top lever left or right. It should not move sideways at all. Also, there should be enough spring pressure on the wedge that you can barely move it with finger pressure. I suspect something is broken in the lockup wedge assembly and you may need a gunsmith who knows Cooeys to help out. If you decide to dis-assemble it yourself be aware that those springs are under significant compression and may really fly ... Good luck
 
Thanks guys, I just read through that thread. I have the same problem as the other gent - locking wedge is very easy to move, and watching it move as I operate the lever, it is also slightly loose in the action. There appears to be 3/16" of space on either side of the lever on the pin it rides.. which lets it slop side to side when activated.

Spring appears intact and properly located. When the lever is at rest there is some space until it takes up the spring.. so the wedge is bottoming as far as it can.

Here are some much better pictures.

IMGP2950_zpsd71dc3f4.jpg


IMGP2953_zpsccd5e6a8.jpg


That wedge is kind of crooked looking and the very bottom edge of the breech is ugly. I have never seen another of these to compare with, so I don't know what is good or bad. Thanks very much for the help so far - I am learning fast!

If I were to put one of these springs in a coil spring tester, or try them with a fish scale, any idea what sort of rating I should get?
 
Well, I took it in to work and fitted a very slightly longer and stiffer spring for the take down mech.

The hammer spring was easy, the small spring was easy but MAN that take down spring!!

I also soaked, cleaned, and lubricated everything.

I have to go shoot it to test it now. I will report back.
 
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