MDT Metal Mag Issue

[whatsupdoc]

Having feeding issues with my MDT 10 round metal mags in 3 lug actions, I am getting random failure to strip a round out of the magazine where the case does not come up correctly and the bolt rides over it. At that point if I touch the bullet pushing it down the bolt will strip the round correctly. It appears that the back of the cases are not lifting all the way up. This happens on my Nucleus in an MDT chassis and my RPR.

On my 2 lug actions they work fine.

Anyone have this issue and come up with a solution?

 

[gnochi]

Without the bolt in the action, and with a round in the inserted magazine, how do the chamber and primer line up?

 

[Praeger]

With a round in the magazine, mag inserted, with the bolt just forward enough to touch the back of the top round as if you were about to chamber the round. How much of the bolt nose is contacting the case head? Now perform the same check on your 2 lug action. You will probably see that the 2 lug action has more overlap (two circles stacked on top of each other - bolt nose & case head). It varies action to action.

You can open up the mag feed lips to raise the top round. Even .020” - .040” is enough to solve the problem and increase the overlap between the bolt nose and the top of the case head. Make mag lip adjustments evenly, and in very small increments. It often doesn’t take much. Use a mag lip tool like MPA sells, or smooth jaw parallel plyers.

 

[whatsupdoc]

I may have found the issue, the mag lips only contact the case at the very front of the case, right at the shoulder. This allows the back of the case to rock up and down in the mag.

I opened up the front of the feed lips slightly allowing the back of the case to make contact with the mag lips. This seems to reduce the rocking up and down of the case head.

We shall see.

Here is a pic of my Nucleus before I did anything. Bolt case contact appears fine.

 

[lead ƒarmer]

I have this same problem with the metal MDT 10 and 12 round mags. I've tried them in Bighorn TL3, Tikka T3, Savage, ARC Nucleus, and Curtis Vector. They all start skipping over round without picking up at some point. Maybe I need to mess with the feed lips, but they have issues in so many different actions I think its a design flaw.

 

[Praeger]

I have this same problem with the metal MDT 10 and 12 round mags. I've tried them in Bighorn TL3, Tikka T3, Savage, ARC Nucleus, and Curtis Vector. They all start skipping over round without picking up at some point. Maybe I need to mess with the feed lips, but they have issues in so many different actions I think its a design flaw.

I don't know how you got it to skip over a round in a Curtis Vector, the MDT metal mag blocks the bolt. MDT web site lists that the metal mag won't work in the Axiom/Vector, Deadline, Tempest, and other three lug actions.

 

[whatsupdoc]

The case protrudes into the bolt head path about the same 3 lug and 2 lug.

When I load a round in a AI mag or an Accurate mag the case is held firmly against the feed lips. In the MDT mag, lightly touching the back or the front of the round will cause the round to see-saw pivoting where the case shoulder contacts the feed lips.
This does not happen with the other two magazines.

 

[Praeger]

Looks like plenty of case protruding to make contact with the bolt nose. The feed lips should be making uniform, full, uninterrupted contact with the case. Can you adjust the feed lips to make proper contact?

 

[308pirate]

You're not the first to have issues with the feed lips on MDT steel magazines. I got hammered here for daring to say that MDT steel mags are less than unicorn farts. On the one I bought, the feed lips had almost no contour to them so the only point of contact between them and the cartridge case was right at the top inside edge of the lips. This led to extremely rough and difficult feeding of the first two rounds and left a pair of axial scratches on every case.

My other steel magazines (the much hated Alpha Industries) have feed lips that are contoured almost perfectly to the curvature of a 308-family case and the rounds feed like butter out of them. Almost as smooth as AICS P-Mags which are for me the gold standard for effortless feed.

 

[whatsupdoc]

Looks like plenty of case protruding to make contact with the bolt nose. The feed lips should be making uniform, full, uninterrupted contact with the case. Can you adjust the feed lips to make proper contact?

That is what I did, will test the mags and see if the issue is resolved.

You're not the first to have issues with the feed lips on MDT steel magazines. I got hammered here for daring to say that MDT steel mags are less than unicorn farts. On the one I bought, the feed lips had almost no contour to them so the only point of contact between them and the cartridge case was right at the top inside edge of the lips. This led to extremely rough and difficult feeding of the first two rounds and left a pair of axial scratches on every case.

My other steel magazines (the much hated Alpha Industries) have feed lips that are contoured almost perfectly to the curvature of a 308-family case and the rounds feed like butter out of them. Almost as smooth as AICS P-Mags which are for me the gold standard for effortless feed.

The fanboys here loose their minds if you criticize their stuff, as you well know.
You are correct about how hard it is stripping the first two out of the MDT mags, and there is minimal case contact with the fed lips.

 

[MDT_Josh]

For any issues with the magazines, feeding or loading, be sure to contact our customer support team here, email us at [email protected] or call us day or night at 1-604-393-0800! Magazines are an incredibly tricky thing to make "one-size-fits-all" and we are more than happy to help you out with whatever issues you're encountering.

- Josh

 

[PracticalTactical]

I have a number of AICS pattern mags that were not reliable, (MDT and Accurate Mag) but I also have some real AICS mags that are reliable, so I measured the spacing between the feed lips with a Vernier, both at the front and at the back.

What I found was that the mags that gave me trouble had the feed lips closer together toward the front of the mag.

This lead me to conclude that as the round is stripped forward it develops a lock to the feed lips and binds.

So to fix it I bent the lips outward until parallel.

How I did that was I placed two paint can stir sticks between the feed lips. Between the stir sticks I inserted a large flat screwdriver.

I turned the screwdriver to create outward force, just a little at a time.

It took a few tries but I got it, and now the mags that were not reliable are very reliable.

Just keep an eye on the spacing so you don't get too wide.

There's probably a better way to shape the feed lips, but this low tech fix worked for me.

Rumor has it that the Accurate Mags sold by Cadex get their feed lips adjusted by Cadex before being sold... Just a rumor, but it sounds right.

 

[mmlook]

all metal mags need to be tuned to your chassis and action

I recently had to readjust my accurate mags, after dropping them a couple times for reloads.

I'm quite surprised how soft AICS/style mags are, compared to pistol mags

fyi,
MPA makes a nice feed lip adjustment tool

MPA Mag Feed Lip Adjustment Tool - MasterPiece Arms, Inc.

This tool comes in handy when adjustments are needed to the feed lips of your metal AR15, AR15 or Bolt Action Box Magazines to improve feeding. If your feed lips get tweaked, if you drop your magazine or simply have feeding issues due to feed angle of your loaded cartridge, then use this tool to […]

masterpiecearms.com

 

[JLP.Payette]

Having feeding issues with my MDT 10 round metal mags in 3 lug actions, I am getting random failure to strip a round out of the magazine where the case does not come up correctly and the bolt rides over it. At that point if I touch the bullet pushing it down the bolt will strip the round correctly. It appears that the back of the cases are not lifting all the way up. This happens on my Nucleus in an MDT chassis and my RPR.

On my 2 lug actions they work fine.

Anyone have this issue and come up with a solution?

I had problems with them in my Nucleus. the back off the case would point down after the bolt was dragged across it and when coming forward it wouldn't pick it up. I contacted MDT and sent my old ones back and they shipped replacements. The replacement 10 rounders work great. I took the mags apart and it appears the replacements have a 3d printed piece on the end of the spring.

 

[whatsupdoc]

I had problems with them in my Nucleus. the back off the case would point down after the bolt was dragged across it and when coming forward it wouldn't pick it up. I contacted MDT and sent my old ones back and they shipped replacements. The replacement 10 rounders work great. I took the mags apart and it appears the replacements have a 3d printed piece on the end of the spring.

Could you possibly post a picture of the of the modification?

 

[JLP.Payette]

Could you possibly post a picture of the of the modification?

 

[whatsupdoc]

Thanks, hard to tell from the picture but are there holes in the spring that the plastic piece attaches to?

 

[JLP.Payette]

Thanks, hard to tell from the picture but are there holes in the spring that the plastic piece attaches to?

Appears to be a friction fit. I haven’t tried removing them, I’m not sure what purpose they serve. Maybe it’s so the spring can slide freely on the bottom plate.

 

[MDT_OFFICIAL]

Appears to be a friction fit. I haven’t tried removing them, I’m not sure what purpose they serve. Maybe it’s so the spring can slide freely on the bottom plate.

It was part of an update with our ten round magazines which aids in the assembly of the magazine.