Magazine Spring Issue???

[gt_diesel]

I have been doing some feeding tests on my new CZ 550 in 500 Jeffery... This is what I have found. Testing was using Nosler Safari Ammo (Nickel Plated / 570 Grain Solid)

If I put three rounds in the magazine, the gun seems to feed fine most of the time... On occasion I have had the tip of the round raise too high, contacting above the chamber. This happens more when cycled slowly. Quick cycling seems to not give the nose to raise as high.

The second issue seems to occur almost every time. When loading three rounds with an empty chamber. When cycling the bolt to chamber the first round, it will eject that top round from the magazine.

The third issue which happened once, is with two in the magazine, one in the chamber. Upon cycling to eject the first round, the second round will also eject.

My observations with this is that the spring seems to be weaker than what I have had previously with my old 416 Rigby. I am unsure if this can be the cause of the problem.

I have also noted that on occasion when loading rounds into the magazine, one will occasionally “pop out”.... It seems to be that the spring is either not holding the round tightly enough to the top of the magazine, or it is opened up too much and not allowing a good seating position for that top round.

I am aware that people have had issues with the nickel plated ammo, I have yet to try any of my standard brass case ammo.

I did email the CZ custom shop to see what the issue may be.

Any options or advice would be great. I am not a huge fan of sending stuff out if it is as simple as a spring issue.

Thanks!

 

[CTDolan]

First, as you mention, try brass. If this solves the problem with rounds popping out of the magazine, you can then address the other issue with the nose of the bullet contacting the edge of the chamber. Likely, brass cases will make this problem (rounds jamming on the edge of chamber) worse but at least then you'll not have competing issues to address (wanting a round to leave earlier so as to line up with the chamber better, all the while not popping out prematurely).

 

[gt_diesel]

The nickel plated actually seem to be coming out too early as they are hitting the top of the chamber, not the bottom.

I will try the brass when I get home and will also rough up the nickel to see if that solves the problem.

Thanks!

 

[gt_diesel]

After speaking with Harlan at Triple River, he said the rails need to be undercut.

The good part is it’s warranty work... The bad is that I have to take the time to pack it up, send it and be without it for a few weeks.

 

[colorado]

I would have Harlan also machine the magazine follower to better fit the fat 500 Jeffery case. My guess is it's machined for the 416 / 450 Rigby case. That was the final fix for my my CZ 550 in 500 Jeffery. Say hello to Harlan for me. If you want I can post a picture of my follower.

 

[gt_diesel]

If you could post a picture that would be awesome!

Thanks

 

[colorado]

ok be an hour or two but I will get on it.

 

[colorado]

Ok here's a picture of my magazine follower you can see where it was machined to make it a bit fatter towards the rear. Kevin Weaver, my local gunsmith did it. I had Harlan and then Wayne at AHR work on my rifle and they got it close. This was the finishing touch. It feeds and functions flawlessly thanks to the work of all three awesome gunsmiths. The 500 Jeffery is not an easy cartridge, but it's an awesome one.

My follower:

My rifle

 

[Nhoro]

Hi gt_diesel,
I have spent a few hours(maybe days) getting CZ 550 to feed properly, you can read my story at https://www.africahunting.com/posts/507417/.
My advice to you is to take it to a good gunsmith. 500 Jeffrey is notoriously hard to get to feed reliably. IMHO it is a bit fat for CZ actions. From your description, the magazine box sounds a little narrow. Sometimes recoil causes the magazine box to bend inwards and the rounds pop out as you describe. You can see this by eye and simply bend the magazine box side outwards If it is the BOX. If it is the reciever part of the magazine (ie just under the rails then take it to a good gunsmith)
Undercutting the rails in essence widens the receiver, just under the rails and allows the rounds to sit wider. This means the spring tension of the magazine follower pushes rounds outwards against the sides of the magazine and rails instead of up and out of the magazine.See Von Gruffs post on correct mauser magazine dimensions. That explains in detail. Then when the receiver is correct, a gunsmith will tune the rails to get the round to release at the right time and will adjust the ramp to stop the nose from bumping. Bottom line, take it to a good smith cos the DIY solution is a load of work and a misstep results in a mess.

 

[gt_diesel]

Thanks guys, it is going out to Harlan at triple River this week. If that dosnt solve the problem, my next step is the AHR improvements.

 

[Shootist43]

gt_diesel, send Harlan (and his daughter) several inert rounds to function through your rifle. BTW they fixed my 404 Jeffery that had similar feeding problems.

 

[Philip Glass]

I have been doing some feeding tests on my new CZ 550 in 500 Jeffery... This is what I have found. Testing was using Nosler Safari Ammo (Nickel Plated / 570 Grain Solid)

If I put three rounds in the magazine, the gun seems to feed fine most of the time... On occasion I have had the tip of the round raise too high, contacting above the chamber. This happens more when cycled slowly. Quick cycling seems to not give the nose to raise as high.

The second issue seems to occur almost every time. When loading three rounds with an empty chamber. When cycling the bolt to chamber the first round, it will eject that top round from the magazine.

The third issue which happened once, is with two in the magazine, one in the chamber. Upon cycling to eject the first round, the second round will also eject.

My observations with this is that the spring seems to be weaker than what I have had previously with my old 416 Rigby. I am unsure if this can be the cause of the problem.

I have also noted that on occasion when loading rounds into the magazine, one will occasionally “pop out”.... It seems to be that the spring is either not holding the round tightly enough to the top of the magazine, or it is opened up too much and not allowing a good seating position for that top round.

I am aware that people have had issues with the nickel plated ammo, I have yet to try any of my standard brass case ammo.

I did email the CZ custom shop to see what the issue may be.

Any options or advice would be great. I am not a huge fan of sending stuff out if it is as simple as a spring issue.

Thanks!

I have had similar problems with my Rugers (.416&.375). Especially the ejecting a spent round hard and the second round popping out. I took them to Matt at Hill Country Rifles who accurized them and had some work done. He did replace the mag spring and I’m hoping that will help. Seems to be more problems with solids.
One thing is for sure a DG gun has to be put through some hard testing and must function all the time to have any value as a DG gun.
Best of luck and keep us posted.
Philip

 

[colorado]

Agree my test is to run 100 dummy rounds through it, fast, slow, upside down. If it doesn't pass it needs more work. Of course shoot it a lot offhand at the range too. I have about 400 rounds through my 500 Jeffery. Only two on game, both as you would expect on North American game were one shot kills.

 

[hgr2]

gt_diesel, I had a similar issue on my M70 416, took some trial and error but its 100% now. Even though it's not a CZ the link below will show the steps(and a lot of other BS)it took to resolve the issue. https://www.africahunting.com/threads/minor-issue-or-life-threatening-problem.16159/

 

[Carsten]

After speaking with Harlan at Triple River, he said the rails need to be undercut.

The good part is it’s warranty work... The bad is that I have to take the time to pack it up, send it and be without it for a few weeks.

Would anyone care to share a couple of pictures of how the undercut is done?
I have the same issue with a CZ 550 and rounds popping out.

 

[Ontario Hunter]

Would anyone care to share a couple of pictures of how the undercut is done?
I have the same issue with a CZ 550 and rounds popping out.

Wow! Not good PR for CZ seeing this defect occurring so frequently. The feeding rails are obviously not machined correctly. Cut too narrow. This could be a very difficult or very easy fix. Possibly the throat of receiver adjacent to magazine box can be opened up slightly. Not difficult but have to be careful or it will result in the issue encountered on another recent thread: bolt wandering out of the guiding rails during cycling. Otherwise fixing this will require adding metal to the feeding rails and remachining them to correct dimensions. CZ should be fixing this even if it means replacing the action/gun.

 

[Carsten]

Wow! Not good PR for CZ seeing this defect occurring so frequently. The feeding rails are obviously not machined correctly. Cut too narrow. This could be a very difficult or very easy fix. Possibly the throat of receiver adjacent to magazine box can be opened up slightly. Not difficult but have to be careful or it will result in the issue encountered on another recent thread: bolt wandering out of the guiding rails during cycling. Otherwise fixing this will require adding metal to the feeding rails and remachining them to correct dimensions. CZ should be fixing this even if it means replacing the action/gun.

My rifle is built on a CZ 550 Magnum custom action.
It is not born as the 500 Jeffery it is now.
The problem is not the rails but the area underneath the rails.
A standard 550 magnum action is a bit too narrow for a fat round like the Jeffery and the rounds are not spread wide enough.
There is plenty of material in this area and it actually looks as if material is left on purpose so it can be customized to the caliber.

 

[Ontario Hunter]

My rifle is built on a CZ 550 Magnum custom action.
It is not born as the 500 Jeffery it is now.
The problem is not the rails but the area underneath the rails.
A standard 550 magnum action is a bit too narrow for a fat round like the Jeffery and the rounds are not spread wide enough.
There is plenty of material in this area and it actually looks as if material is left on purpose so it can be customized to the caliber.

That clears it up. I faced a similar challenge converting an 8mm standard Mauser action to 404 Jeffery. I had to remove significant metal below the feeding fingers to accommodate the much wider 404 rounds. A Dremel tool with tiny grinding wheel did the job. I purchased aftermarket 416 Rem Mag bottom metal and started by removing enough metal from the bottom throat of receiver to make it match the untouched bottom metal opening.

 

[colorado]

Have you touched up the magazine follower as well to adapt it to the fatter 500 Jeffery cartridge? Kevin Weaver did that for me and it fixed the feeding problems on my CZ 550 in 500 Jeffery.

 

[Nhoro]

Would anyone care to share a couple of pictures of how the undercut is done?
I have the same issue with a CZ 550 and rounds popping out.

I used a drill and rotary rasp. You could use a dremel and stone. You grind from the feed lip down below the contact area where the cartridge case touches the cartridge ( basically come down the radius of the cartridge.) Bit be aware this makes the cartridge move further left or right while feeding ie it may over shoot the chamber left or right. All changes need to be balanced- feed ramp vs magazine width vs feed lips adjustment.