.44 Mag MKIIV Last Round Hold Open Issues

[Sulaco83]

Hi Folks, I bought a lightly used MkIIV a couple years ago and it's been great. The only issue I have is that with a couple of the mags, the slide will not lock on an empty magazine. After playing with the ones that are failing, I see that the issue seems to be that the "button" on the mag follower is skipping over the slide catch instead of pushing it up. If I slide the mags in gingerly I can get them to lock the slide back, but if I slap them in they will jump over the slide catch. I only have this issue with 2 of the mags which are older, the other 3 seem to be fine. Does anyone have any tips on how to correct this? Mags are expensive and I would hate to just stop using them. I looked for some replacement springs for the follower but only saw the large mag springs. Thanks in advance.

[MrBlackCat]

Hello Sulaco83...
You can order the springs from Magnum Research directly, but they aren't listed on the website as far as I know. Actually you can order standard part at this number... 218 746-3459. This isn't the same as the web-shop location. It is called a Magazine Catch Spring, but I don't have the number handy. They will know what you are talking about though.

It does sound like something is worn a bit or out of position... the problem might not be entirely an issue with the magazines, it just might be worse with some. Are these all factory magazines, or are any of them ProMag brand? ProMag magazines can be very problematic is why I ask.

Another possibility is that the Slide Lock Lever is worn on the edge where the magazines catch it. This can happen over time, but can also happen more quickly if the pin (that passes through both sides of the frame) of the magazine catch lever, become bent just slightly. This can allow the slide lock lever to not sit flush against the frame and the actual "nub" which the magazine catch engages, might not get a positive catch with the magazine follower pin.

I have never had to replace a magazine follower catch spring... in magazines made in the 80's. To have multiple springs bad would be highly unusual to me. If this IS caused by wear of the Magazine Catch Lever, it can most likely be fixed by squaring it off with a file or Dremel tool... or just replaced.

Good luck...

MrBlackCat

[Sulaco83]

Thanks MrBlackCat, they are all factory mags however the two with issues are older "95" marker as opposed to the "08" marked ones that are working better. My thoughts went to springs because the newer ones have springs that are much stiffer, which I thought might be making the difference. Wouldn't the mag catch spring be the spring for the button for the mag catch itself though?

I'll have to pull out the slide lock lever and inspect it for wear, but it does seem to be sitting flush. I wonder if it could somehow just be slightly shorter than it should be. The entire gun looks like it's barely been shot so I'd be really surprised if parts were worn out.

[MrBlackCat]

Thanks MrBlackCat, they are all factory mags however the two with issues are older "95" marker as opposed to the "08" marked ones that are working better. My thoughts went to springs because the newer ones have springs that are much stiffer, which I thought might be making the difference. Wouldn't the mag catch spring be the spring for the button for the mag catch itself though?
Yes, the Magazine Catch Spring absolutely is for the button return itself. Sorry about that. I am simply wrong on that one. I found the springs I have for the catch in the magazine follower, four in a bag, but the bag is not marked with any number or identification, other than a Magnum Research logo bag. I have no idea when I got them, but I have never needed them.



I'll have to pull out the slide lock lever and inspect it for wear, but it does seem to be sitting flush. I wonder if it could somehow just be slightly shorter than it should be. The entire gun looks like it's barely been shot so I'd be really surprised if parts were worn out.I wouldn't bother... if it is bent enough to cause the issue I described, it is pretty obvious.

I realize now you are talking about the actual magazine follower springs. You can test this by swapping one of your new ones for one of the old ones of course. Only takes a second to change them. You can also compare them when you have them both out. If the older ones are like an inch shorter, they are likely getting weak enough to cause issues.

I just pulled a couple of 44 Magazine springs and they measure 6-1/2 inches. New ones measured 7 inches. I have no issues with them at these lengths even with 300gr projectiles. That might give you a reference to check from.

Chances are that if you can feel much difference between the strength of the springs between magazines, then they may need replacing. I don't replace mine until there are issues with function, and they can really get squished a bit over time, but still function. I have 357 Magnum springs right at one inch shorter than new, and they still function fine... but 357 is a lot lighter round to lift than 44 Magnum.

Let us know what you find! :)

MrBlackCat