Cartridge stop problem

[Zach H.]

Hello everybody! I have an 88'-89' 500A (the same one with the roll pin holding the trigger group in place) that is functionally a single shot right now. After many inert shells being loaded & few cycled, it seems to be a piece called a "cartridge stop" that is preventing the rounds in the magazine tube from being fed onto the shell elevator. I'm assuming that one of the pieces inside push the cartridge stop out of the way enough to let 1 round out of the mag tube but is not pushing it far enough out of the way. I've taken it apart & tried to take some of the bend out of the cartridge stop. Once the correct trigger pin is delivered by USPS, I'll put it together to see if it feeds correctly. Has anyone had a similar problem? Am I correct in trying to straighten the piece out? If it still does it when I reassemble it, I'll post pictures of the issue.

 

[Ernst]

Zach, recommend you take a look at this video which illustrates in detail how the action works. Look closely at the functions of both the cartridge interrupter and the cartridge stop.

Both these are cheap replaceable items if needed. Many find that taking all the finish off these and the shell lifter with scotchbrite improves their function.

 

[old mossy]

You are on the right track as far as the bend in the cartridge stop. Mossberg has had a problem with them in the past.
Below is a picture of a good cartridge stop, and a bad one, as far as the bend. The first pic is the bad cartridge stop,bent too much.

 

[Zach H.]

Wow our bad cartridge stop pics almost match

Before cycling the action


After cycling the action

I'd say it's the cartridge stop being bent too much.

 

[old mossy]

From what I see it needs to be "on the shell" a bit more in the second pic.

Since you got the trigger pin out, have you torn down the gun and give it a good cleaning?

 

[John A.]

I have had that happen to me before.

The slide/bolt is what pushes it over to the side out of the way as it's cycling rearward. Think of the stop like you would a piece of spring steel sheet in principle.

If it's not moving far enough over (not enough outward bend in the center for the bolt to push up against it hard enough) it won't let the shell out of the mag.

If it's bent too much causing the stop to move over too far inside of the little groove it fits in, it may double feed the action by allowing more than 1 shell to feed out of the mag at a time.

So, it's a matter of very slight bends until you get it just right.

New ones don't cost much though if you can't get it just right. ~$20

 

[Zach H.]

From what I see it needs to be "on the shell" a bit more in the second pic.

Since you got the trigger pin out, have you torn down the gun and give it a good cleaning?

The 2nd pic is after cycling the action. The dummy round was never fed onto the shell elevator and I'm guessing it's as far as the cartridge stop got moved. I can see the shell elevator moving the cartridge stop but it's just not enough.

And yes, I cleaned all kinds of gummy oil out of it

 

[John A.]

The 2nd pic is after cycling the action. The dummy round was never fed onto the shell elevator and I'm guessing it's as far as the cartridge stop got moved. I can see the shell elevator moving the cartridge stop but it's just not enough.

And yes, I cleaned all kinds of gummy oil out of it

That stop just needs the bend/angles fixed.

If you have the stop out, look at where the "peak" of the bend is. Bend it a little more where on the side that contacts the bolt would be pushed outwards towards the bolt a little more. That will by default cause the tip of it to be closer to the receiver and hopefully allow it to move over farther into the channel so the shell will pop out.

Even if it takes 5 or 50 times to get it right, you can do it.

Look at the pictures of where the stop is on the back of the brass in this picture and try to get it close to this and it should feed.

 

[Zach H.]

It appears upon further investigation that the action bar arms (the arms on the pump slide) have a beveled edge that push the cartridge stop in against the receiver and it is not pushing it in enough

I hope the picture shows where the problem is (in my mind for now). It doesn't seem bending the cartridge stop would help the issue.


I think the cartridge stop is catching the shell at the right position, it's just not being pushed against the receiver enough by the action bar.

 

[Zach H.]

This beveled edge on the left action bar arm is what moves the cartridge stop out of the way letting a shell onto the shell elevator.

 

[old mossy]

Do you think it's bent? Sounds like you found the problem.

Keep us posted.

 

[Zach H.]

Do you think it's bent? Sounds like you found the problem.

Keep us posted.

I feel like the problem lies in the relationship between the left action bar & the corresponding cartridge stop. When the action is cycled open all the way, the beveled edge of the left action bar isn't moving the beveled edge of the cartridge stop enough. It's as if there's too much material removed or missing on one or both of those items.

Is this milling on the bottom of the left action bar normal? I feel like I wouldn't have this problem if it didn't have this recess in the action bar. It's like the cartridge stop is riding in this groove & not being pushed to the receiver enough.

 

[Zach H.]

I bought a cartridge stop from Mossberg but figured I'd try my hand at modifying the existing one since, if I screw it up, I have another one on the way. I used a Dremel to take off material on the hooked end, lightly going over the flat face of the stop and reinstalling to test retention & feeding (and repeated the cycle) until it functioned with snap caps. I took it out today to test it with live rounds at an annual Thanksgiving day shoot. Surrounded by high end Brownings & fancy shiny Italian O/Us, everybody was interested in the pistol grip pump. It worked flawlessly through every round. The pattern isn't as wide as I thought it would be for being a shortened barrel with no choke.

 

[John A.]

I'm glad you got the old gun working enough to put some shells through it.

I believe that once the new parts come in, I'd put them in the gun and use the modified ones for spares. But, I'm glad you got to give it a work out today.

 

[Daryll]

I had a similar (but opposite!) problem with my Hatsan MPA.... I hadn't used it for a while but got it out ready for a practical shotgun comp, and tried a couple of snap caps through it (look like the same snapcaps as Zach has).
I loaded both in the mag, then racked the action... both snapcaps popped out of the mag at once and jammed on the lifter.

After much tinkering I couldn't find anything wrong with the gun, so went to Google... it seems that Hatsans don't like shells less that 70mm (2 3/4'')..and the snapcaps are only 60-65mm
When i went to the comp I managed to do some test firing beforehand, and using some 2 3/4 shells it worked flawlessly.

What i'm getting around to saying, is to try shooting the gun with a variety of shells, and see if some work better than others..

 

[Zach H.]

What i'm getting around to saying, is to try shooting the gun with a variety of shells, and see if some work better than others..

It wouldn't cycle any of the shells reliably. Most were better that trying to cycle the snap cap but not enough to trust on a home defense gun. I'm guessing that the brass offered a more slippery surface than the snap cap but still didn't cycle every time.

 

[old mossy]

I made my own snap caps from some of the fired shells I fired from my 500. I keep it loaded with Fiocchi 00 buck for HD and that is what I made the dummy rounds from.
Making sure they were the same length and same weight as a new unfired round. (pennies are good for getting the correct weight)
I did this to eliminate other problems with cheap snap caps.

 

[Zach H.]

That's an awesome idea!

I wish I had the space to get a reloader

 

[John A.]

The Lee Load-All 2 is not big at all.

It's maybe 14 inches wide, 20 inches tall and 6 inches deep from front to back. And the better news is, they are usually around $60.

And you can get 20 gauge and 16 gauge parts separately if you wanted to load either of them too, so it's not a 1 trick pony.

Finding powders and primers right now is the hardest part.

Ballistics products sell a ton of different wad styles and will even sell their load data for some of their european shells and wads. Which obviously aren't as common here in the US.

Myself, I like smooth sided Remington hulls the best. The Remington STS are usually cheap when you find them in the store, and are the smooth hulls. Plus, the smooth body hulls tend to feed great in just about everything. I've reloaded some of them more than a dozen times a piece with no splitting or cracking.

You generally use the figure 8 wads in the Remington hulls since that's what are loaded by the factory.

You can buy genuine remington wads or aftermarket brands. Examples:

https://www.ballisticproducts.com/Remington-12ga-Figure-8-wad-500_bag/productinfo/030RFIG8/

https://www.powdervalleyinc.com/product/claybuster-12-ga-rem-figure-8/

My favorite part about reloading is that I can go from very mild low brass handicap loads that have hardly any recoil at all, to 1400+ fps barn burners that kick like a mule. Plus you can load either birdshot or buckshot or even slugs into the shells all the same with no difference in anything. The gun/powder doesn't know the difference between a 1 ounce load of tiny pellets or 1 ounce slug (for example). So, reloading your own gives you a lot of versatility.

I also know that many people don't like using steel shot pellets because they aren't as dense as lead and don't typically penetrate as far as lead will, but I've been using a lot of steel ball bearings in my triple ought buckshot loads. I got a 1500 count pack of "ball bearings" from amazon for about $15.

Try doing that with store bought lead buckshot.

(spoiler alert: you can't).

So, basically, I got enough steel pellets to load almost a whole case of buckshot shells that generally cost $1 a pop for the cost of a large pizza.

 

[Ernst]

Zach, John's recommendation is right on; however, if you're not in a hurry nor loading massive quantities of shells you can fabricate you own reloading tools using a wooden dowel and a long shaft punch. You only need a set of powder dippers (or a balance scale) plus the components. I don't do roll crimps but use a hornaday crimp starter for star crimps. Some folks use a little melted wax to seal the shell vice crimping. There are several videos online showing the process.

I've been using this method for years and even reload shells in the field. It's not as fast a a bench loader but works well and takes up no room.

Regards