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MDT 223 Steel mag issues

Fullbore1912

Private
Minuteman
Aug 28, 2022
44
5
ND
I am currently on my fifth mag and MDT is sending a polymer one to test but there isn't anything else they can do since its within their spec and the suggested contacting XLR. I don't think they will have much to say as I have all ready tried to adjust the mag catch. Also I have ZERO issues with their 6BR mags on this same action and Chassis.

Build is a Terminus Zeus, XLR Envy Pro, and a proof prefit .223 Rem.

The mags are bending at the plastic lip and causing the following issues.

1. When seating the mag the case is slightly released causing a jam or it fully dislodges one or more cartridges
dislodge_AdobeExpress.gif

2. The mags release the case early from the polymer "extended feed lips" causing the rear of the case to pop up pointing the tip of
the bullet down and jamming. (See picture with red line indicating last position the mag holds the case)

Jam.gif


As far as I can tell with my basement gunsmithing degree these are the causes/fixes

The polymer sleeves have a loose fit between the case and the steel lip that flexes when under pressure releasing the case when seating.

When it comes to the bullet tipping down I can only assume that if the flex was removed along with the extended polymer lips the rim would catch on the case and tip the cartridge up before release rather than pointing it down.

Any help is appreciated. starting every PRS stage with a jam is no fun.

UPDATE: MDT poly mag runs perfectly
 

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Might just be missing something obvious here but did you try Accurate-Mags to see if you could replicate the issues?

6BR with different mags/bolt is not really a 1:1 comparison.
 
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Might just be missing something obvious here but did you try Accurate-Mags to see if you could replicate the issues?

6BR with different mags/bolt is not really a 1:1 comparison.
I haven't yet, everyone i know uses these. I was hoping not to buy new mags.
 
No issues with the 223 AICS Accurate-Mags in my CDG.

The metal lips on the Accurate-Mag are the same length as the polymer. The cartridge is not released from the magazine until it is pushed past the feed lips.
 
I recently bought one of the MDT dssf steel 223 mags to test as I liked the shorter height, but the partial metal, partial plastic unsupported feed lips do not function as well as the accurate mags that have the entire length of the plastic liner feed lips supported by metal. The plastic portion of the MDT feed lips beyond the metal is too flimsy and releases the round early. I've also noticed on the MDT you can pull a round straight out of the feed lips like is happening to you when you seat the mag.

Another vote for trying an accurate 223 mag, they're taller being single stack, but in my experience they work better with the feed lips being fully supported by metal. I've used the accurate mags in 2x R700s, a Tikka, a nucleus, 2x Archimedes, and an AXSA.

I did not care for the MDT all plastic 223 mags, while they were cheaper and functioned ok they were very "draggy" on the case when pushing the bolt forward to strip a round off a full or near full mag, you really felt the extra effort needed to push the bolt forward.

To this day my all time favorite AICS 223 mags are the genuine AI 223 mags. They always fed like butter, had a reasonable height, and worked great. Too bad the ones made near the end of the run before they were discontinued had a bad habit of coming apart at the seam.
 
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I ran into issue number 2 with my Zeus in .223 using the MDT metal .223 magazine. However I also have the older style MDT full polymer magazines and they work like a charm so I haven't really spent much time troubleshooting. The mag did seem to work better with shorter OAL ammo so my guess is the feedlips are too long.
 
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Accurate mag has an extended version too where the polymer goes past the metal.

I would try to find a non extended feed lip mag and see if that works. The extended were only necessary for me to feed 223 into a ruger American where the cartridge becomes otherwise completely free before it starts into the chamber; everything else the nonextended seem to be best.

Can you pull up a round by the tip through the feedlips by hand? The metal should still prevent that but I’m assuming since one bounces free that they aren’t closed enough. I’ll try to measure mine in an hour if I can remember to compare to your .320-.327 dimension.

Edit: Depending on the metal mag mine are .295-.320 wide, my old plastic actual aics is .340 but muuuuch thicker feedlips that won’t spread
 
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I recently bought one of the MDT dssf steel 223 mags to test as I liked the shorter height, but the partial metal, partial plastic unsupported feed lips do not function as well as the accurate mags that have the entire length of the plastic liner feed lips supported by metal. The plastic portion of the MDT feed lips beyond the metal is too flimsy and releases the round early. I've also noticed on the MDT you can pull a round straight out of the feed lips like is happening to you when you seat the mag.

Another vote for trying an accurate 223 mag, they're taller being single stack, but in my experience they work better with the feed lips being fully supported by metal. I've used the accurate mags in 2x R700s, a Tikka, a nucleus, 2x Archimedes, and an AXSA.

I did not care for the MDT all plastic 223 mags, while they were cheaper and functioned ok they were very "draggy" on the case when pushing the bolt forward to strip a round off a full or near full mag, you really felt the extra effort needed to push the bolt forward.

To this day my all time favorite AICS 223 mags are the genuine AI 223 mags. They always fed like butter, had a reasonable height, and worked great. Too bad the ones made near the end of the run before they were discontinued had a bad habit of coming apart at the seam.
If the polymer mag they send doesn't work I'll try the accurate mags
 
All I have used in multiple .223 bolt guns is the polymer MDT mags and they work great. I got them because I was cheap but after seeing so many people having issues with the steel mags I am happy I did. Try those poly mags.
 
Tried the MDT, Accurate, and AI metal 223 mags in MPA chassis, none of them worked reliably. Went back to the ugly as homemade soap Magpul 5.56 AICS plastic, at least they work all the time.
 
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Accurate mag has an extended version too where the polymer goes past the metal.

Interesting, that most be a newer offering; those weren't available when I purchased mine several years ago, accurate only had one option. On the accurate mags that I have the metal feed lips are as long as the metal supported and extended unsupported plastic feed lips on the MDT metal mag.

Have any pics of the extended feedlip version next to the regular feedlip version of the accurate 223 magazine? I don't see a pic of both versions on accurate's website.

They don't even describe the feedlip differences on the magazine page, you have to look at the replacement insert page to get a description:

Screenshot_20230715-075118.jpg
 
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Interesting, that most be a newer offering; those weren't available when I purchased mine several years ago, accurate only had one option. On the accurate mags that I have the metal feed lips are as long as the metal supported and extended unsupported plastic feed lips on the MDT metal mag.

Have any pics of the extended feedlip version next to the regular feedlip version of the accurate 223 magazine? I don't see a pic of both versions on accurate's website.

They don't even describe the feedlip differences on the magazine page, you have to look at the replacement insert page to get a description:

View attachment 8183145
A newer offering years ago now.
714FE46C-2B56-478A-9639-0D2445F85E51.png


1689433602788.png
 
Thanks for the pic, that's about what I expected. Nice they offer that as an option. Can't say I've ever seen the extended feedlip version offered at a dealer, but I've never looked for them either.

Also nice they now offer replacement liners. Many years ago before any of the 6br mag kits were offered I modded an accurate 223 mag liner for 6br according to a post here, and when I tried to buy a new liner from accurate they wouldn't sell me one saying they could only do warranty replacements and cutting it wasn't covered by the warranty (lol.) At least now you can buy replacement liners right off their website. Guess I'll finally put that one magazine back in service, I'll also buy an extended feedlip liner to test since they're very inexpensive. Not sure it will help with anything but for $10 I'll test one.
 
Why do people want to buy a metal mag with a poly mag in it for $70 when you can buy a poly mag for $40? What is the perceived advantage to the steel?
 
Wow 5 mags and they do that? It’s not an action or chassis issue if it’s puking out a round when seating the mag. Get your money back and buy accurate mags, they run 100%.
 
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Why do people want to buy a metal mag with a poly mag in it for $70 when you can buy a poly mag for $40? What is the perceived advantage to the steel?

Because the plastic feedlips stretch out over time, and yes they do. I’ve thrown plenty of unlined polymer mags away over the years because they’ll no longer hold rounds or they do exactly what his do when you seat them (I’ve had at least a dozen magpul AR mags do this). Metals holds up far better.
 
Because the plastic feedlips stretch out over time, and yes they do. I’ve thrown plenty of unlined polymer mags away over the years because they’ll no longer hold rounds or they do exactly what his do when you seat them (I’ve had at least a dozen magpul AR mags do this). Metals holds up far better.

Guess I will see. LOL Still seems like buying 4 poly mags at $25 at Black Friday and have them run for a few years is a better option than getting a mag that doesn't run reliably but will last forever.
 
Why do people want to buy a metal mag with a poly mag in it for $70 when you can buy a poly mag for $40? What is the perceived advantage to the steel?

In my case, the MDT plastic mags were extremely "draggy" especially when the mags were near full, they easily doubled or tripled the effort needed to close the bolt. It wasn't the bolt body rubbing and binding on the feedlips either.

Put an accurate or genuine AI mag in, and back to nice and light bolt closing effort.

Your experience may vary. If the MDT plastic mags work in your combo, cool... They allow a long OAL and you can't beat the price, which is exactly why I tried them.
 
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Guess I will see. LOL Still seems like buying 4 poly mags at $25 at Black Friday and have them run for a few years is a better option than getting a mag that doesn't run reliably but will last forever.

$25 is a deal but the accurate mags run reliably. They’re the only 223 AICS mags I’ve ever found to run reliably but I haven’t tried the MDT polymer and I wouldn’t because of previous known issues with polymer. The Ruger and AI 223 mags both gave my issues, but the Ruger was reliable until it cracked down the back.
 
$25 is a deal but the accurate mags run reliably. They’re the only 223 AICS mags I’ve ever found to run reliably but I haven’t tried the MDT polymer and I wouldn’t because of previous known issues with polymer. The Ruger and AI 223 mags both gave my issues, but the Ruger was reliable until it cracked down the back.


My MDT polys have been running fine for a couple years now. Feed smoothly and reliably. Might be better quality than the Rugers. Pick one up and try it.
 
My MDT polys have been running fine for a couple years now. Feed smoothly and reliably. Might be better quality than the Rugers. Pick one up and try it.

I’ve already got 3ea of Accurate 5 and 10 round 223 mags and I know better than to buy MDT mags, this guy isn’t the first to have problems with their mags. FWIW I run those Accurate mags in an MDT chassis
 
I’ve already got 3ea of Accurate 5 and 10 round 223 mags and I know better than to buy MDT mags, this guy isn’t the first to have problems with their steel mags. FWIW I run those Accurate mags in an MDT chassis

Fixed it. ;)
 


Here’s two just two threads of many documenting people’s issues, both of which you commented on acting oblivious to issues just like here. The second thread being an overall polymer mag thread that you first directed your attention to a guy having issues with MDT’s.

Why do you have to be such a denier? If they work for you, fine, but that doesn’t mean that they’re overall a reliable mag when a good number of people have so many issues with them that they don’t have with other magazines.
 


Here’s two just two threads of many documenting people’s issues, both of which you commented on acting oblivious to issues just like here. The second thread being an overall polymer mag thread that you first directed your attention to a guy having issues with MDT’s.

Why do you have to be such a denier? If they work for you, fine, but that doesn’t mean that they’re overall a reliable mag when a good number of people have so many issues with them that they don’t have with other magazines.

LOL I'm not a denier but some don't even give them a chance. You can find threads with people complaining about anything on here. If you don't want to use them then don't but they do work fine for me in multiple rifles for years now so I will keep using them. I will consider myself lucky.
 
LOL I'm not a denier but some don't even give them a chance. You can find threads with people complaining about anything on here. If you don't want to use them then don't but they do work fine for me in multiple rifles for years now so I will keep using them. I will consider myself lucky.

You absolutely are a denier and a brand pimp. I’ve read your posts for decades about Vortex and Hornady and more recently Burris. You’re in a thread where someone is having issues telling someone else who has accurate mags that run flawlessly to go try MDT’s.

Anybody who has issues with mags like those or like the OP here has every right to complain. They’ve sent him 5 of the pieces of junk and they puke rounds out and these are magazines that have steel on the outside for support which is much stronger than polymer, do you really think the cheaper polymer ones are better?
 
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You absolutely are a denier and a brand pimp. I’ve read your posts for decades about Vortex and Hornady and more recently Burris. You’re in a thread where someone is having issues telling someone else who has accurate mags that run flawlessly to go try MDT’s.

Anybody who has issues with mags like those or like the OP here has every right to complain. They’ve sent him 5 of the pieces of junk and they puke rounds out and these are magazines that have steel on the outside for support which is much stronger than polymer, do you really think the cheaper polymer ones are better?

Yup my experiences are false and yours are true. Lol Save that shit for someone who doesn’t know any better. I said my experiences in the threads you tried to pull up as “proof” and tried to help a guy by telling him to try them and only told you so you could see for yourself but you would rather be able to come on here and bitch about them so continue your bitch fest.
 
Has anyone tried the magpul poylmer AICS 5.56 pmag. Here a short Magpul video.

 
I tried the .308 version and they had a shorter OAL and their fit was iffy in different mag wells. Looks like the .223 only gives you 2.390" OAL so a little short. My 75 ELDs are loaded at 2.470". A mag, which we shall dare not speak it's name, loads out to 2.550" so works a little better with longer loaded heavier bullets.
 
Im using the 308 aics style also in a XRS chassis with a savage 110 Tactical. Had to slightly file the mag catch to lock into the chassis, but has been working good so far. I also have a CDG coming in 223 so ive been following the mag discussions.
 
Has anyone tried the magpul poylmer AICS 5.56 pmag. Here a short Magpul video.


I have a Magpul AICS .223 polymer magazine but havent used it much on my KRG Whiskey 3 chassis. The MDT poly AICS mags fits snugly into my magwell along with metal AICS mags and metal AW mags. The Magpul fit is very sloppy; it has much more side to side wiggle as well as fore and aft tilt, and much more play around how far it will insert into the magazine well.

Overall:
  • The MDT poly .223 mags fit well and runs a little rough while offering me a nice long OAL
  • The MDT metal .223 mag I have runs like butter (sometimes your not even sure you picked up a round or if the magazine is empty) but gave me reliability issues in the stripped off round would slam tip first into lower breach face of the barrel and not chamber (perhaps ARC's new CDG action and coned breach might fix this). Could also be due to me using a 3 lug action as compared to a 2 lug action like an Impact.
  • The Magpul .223 AICS wiggled all over the place and fit very poorly. I figured why mess with them when the MDT mags were the same price, fit well, ran well, and offered me longer OAL
I am now tempted to buy a .223 Accurate mag just so I can compare them all. We will see...
 
Tried the MDT, Accurate, and AI metal 223 mags in MPA chassis, none of them worked reliably. Went back to the ugly as homemade soap Magpul 5.56 AICS plastic, at least they work all the time.
Same deal. All of the .223 mags just plain suck. Its the main reason I wont shoot .223 at matches , especially the ones inside 600 yards. Too many malfunctions and issues in practice, can barley get through a 10 round mock stage without some kind of feeding issue.
 
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If the polymer mag they send doesn't work I'll try the accurate mags
I kind of prefer the poly mags from mdt even over my metal ones, though all of them feed well in my origin. The poly mags just seem to be a little easier and smoother. I'd bet they will work for you.
 
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Thousands of rounds through Accurate mags / TL3 without issue....... There is always going to be someone with issues, fuck knows why. I was that guy with the BR, doesn't meant everything I tried was shit, just my circumstances.
Pete
 
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The greatest irony is that the best 223 magazine for bolt action, especially for long coal is the DTA/SAC 223 magazine for the Desert Tech ... a platform known for its magazine issues, yet all of the 223 AICS magazine needs grinding, filing, tuning, etc to work and the only ones I manage to make work 99% are the 5 rounds Accurate with 204R with 40gr Berger.
I still haven't fully found a fully reliable combo with 300 BLK with 190 SubX due to the short case and round nose but I'm pretty close to 90%+ reliable with the new MDT 10 round magazine in my Xylo chassis. If we ever get dual stack AW style magazines for 223 rounds, I'm getting another CDG with the 223BF and a coned barrel.
 
I tried an MDT 223 metal AICS mag in my new .223 build. It's a Zermatt Origin in a MPA Matrix Pro running a Bartlein barrel chambered by Southern Precision Rifles. I ran it over last weekend and was very pleased. I was worried that I would have issues similar to yours, but thankfully, mine ran perfectly.
 
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