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CZ Shadow 18-round magazines issues


cheby

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Hi,

I have 5 18-round magazines that I have been using for practice only (I shoot matches with Mecgar mags only).

I have never liked the original mags but they worked okay for around 15K rounds. Recently I started experiencing a lot of FTF issues with those magazines while the mecgar ones work alright. So I bought the +10% springs and finally cleaned the mags:). It did not fix the problem, however. Do I need to tune the mags once in a while or are they just done and good for dryfire only from now on?

Thanks

Edited by cheby
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Hi,

I have 5 18-round magazines that I have been using for practice only (I shoot matches with Mecgar mags only).

I have never liked the original mags but they worked okay for around 15K rounds. Recently I started experiencing a lot of FTF issues with those magazines while the mecgar ones work alright. So I bought the +10% springs and finally cleaned the mags:). It did not fix the problem, however. Do I need to tune the mags once in a while or are they just done and good for dryfire only from now on?

Thanks

Hi,

I have 5 18-round magazines that I have been using for practice only (I shoot matches with Mecgar mags only).

I have never liked the original mags but they worked okay for around 15K rounds. Recently I started experiencing a lot of FTF issues with those magazines while the mecgar ones work alright. So I bought the +10% springs and finally cleaned the mags:). It did not fix the problem, however. Do I need to tune the mags once in a while or are they just done and good for dryfire only from now on?

Thanks

Ask Stuart at CZ Custom.

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I think that the CZ magazines are made from softer metal than the Mec-Gar ones. I've relegated my CZ magazines to dry-fire practice and do all my live fire with Mec-Gar 17-round AFC ones.It's

It's actually thinner. If you weigh a mag body of a CZ 18 rounder and a mag body of a CZ 16 rounder, the mag body of the 16 is actually HEAVIER. Which doesn't make sense to me, unless they realized the OEM rubber grips are wildly heavy and they were looking to save weight

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What kind of feeding issue?

Is it usually the 4th-5th round in the mag that fails to feed?

Yes, that is correct.

I had the same issue show up pretty bad at a major match I traveled to. It was very frustrating but I figured it out after day 1 and stayed up late in my hotel room tuning the issue out. By that time it was too late as I had already racked up 20 seconds worth of malfunctions.

The internal geometry of the OEM SP01 mags is such that the follower loses a little bit of upward tension from the mag spring around the 4th-5th round (when running 10 rounds.) What happens is that the bullet tends to nose dive a little. +10% springs help but it doesn't solve the issue. I was running +10% springs at this match and still had the issue.

What compounds the issue is the feed lips getting banged up from use. As the rear of the case drags on the banged up feed lips, it makes the round want to nose dive even more. Once the round nose dives enough, the case mouth gets hung up on the front of the mag no matter how much crimp you have. A good way to check is to hand cycle some rounds through the gun. If the feed lips are banged up and sharp, you'll see two scratches running down the length of the ejected round.

The solution is to smooth out the feed lips and put a bevel on the front of the mag so even if a round hits, it will still make it out of the mag.

ETA-I use MecGars for matches. They feed much better and don't have the loss of tension/feeding issue. However, after doing the mod that I described above I have not had any issues with the factory mags which I use for practice and indoor matches. Even with +10% springs though, you still get the loose round rattle sound when loading 10 rounds.

Edited by d_striker
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Thank you. I was warned by several people that the OAM magazines are problematic. I guess I need to buy more mecgars...

Smooth out the feed lips and put the bevel on the front with a Dremel and the issue will go away.

Even with MecGars, you should keep an eye on the feed lips. Especially if you don't have separate dry fire mags. A metal frame chews up the feed lips eventually if you're like me and don't always nail your reloads.

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I measured the feed lips of my competition mags and a couple new mags. For two years I have run 2 16's, 2 17 mec gars and 2 18's. Feed lip spread was .345 for new mags and .343-.348 for the 16's and the 17's. The 18's measured .354 and .365.

The 18's are now loaded with 10 empty rounds for dry fire.

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I measured the feed lips of my competition mags and a couple new mags. For two years I have run 2 16's, 2 17 mec gars and 2 18's. Feed lip spread was .345 for new mags and .343-.348 for the 16's and the 17's. The 18's measured .354 and .365.

The 18's are now loaded with 10 empty rounds for dry fire.

Good info. I forgot to mention that in my post as well.

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60k+ rnds on my CZ SP01 mags + all my dry fire. The only feeding issues were directly related to mags springs. I check the lips occasionally and have had to make minor adjustments. I suspect the feed lip issue is from mags being stepped on/damaged during a COF but not certain of that.

I keep the mags clean and always clean mags before major matches with CLP (well almost always -- shot a match in the desert with a lot of wind and dust so cleaned mags and no oil/lub).

YMMV

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60k+ rnds on my CZ SP01 mags + all my dry fire. The only feeding issues were directly related to mags springs. I check the lips occasionally and have had to make minor adjustments. I suspect the feed lip issue is from mags being stepped on/damaged during a COF but not certain of that.

I keep the mags clean and always clean mags before major matches with CLP (well almost always -- shot a match in the desert with a lot of wind and dust so cleaned mags and no oil/lub).

YMMV

Gene-most of my damage to the feed lips was from botched reloads. In other words, the feed lips hitting metal frame on pistol.

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I check the lips occasionally and have had to make minor adjustments.

What adjustments do you have to do? If the feed lip spreads deviate from the brand new is it possible to fix the issue by simply adjusting the spread back to factory spec?

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I check the lips occasionally and have had to make minor adjustments.

What adjustments do you have to do? If the feed lip spreads deviate from the brand new is it possible to fix the issue by simply adjusting the spread back to factory spec?

I have two new mags; never used. Use callipers to compare feed lip measurements. Typically, I find mags with feed lip spread but occasionally, narrowing at the lips. Adjust as necessary to get the lips back as close as I can to the measurements on the new mags. My experience is close is good enough. Don't need measurement in the 1/1000 to 1/10000th of an inch. ~ 1/10 or less is more than good enough. I have one or two mags with minor dents in the sides. Most likely stepped on and with something like a rock under the mag. All work flawlessly regardless of how many rnds are loaded. YMMV

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Where are you beveling the mag?

On the front of the mag where the case mouth would hit when a round nose dives.

Just putting the bevel on without fixing the feed lips is not the solution though. To fix the root cause, you need to 1.) make sure the lips are properly spaced & 2.) smooth out any rough spots on the under sides of the feed lips which contact the round when it's in the mag. The bevel is just extra insurance.

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The feed lips will get banged up. Look at the magwell on your gun. If it looks anything like mine, it's pretty beat up. Guess what's banging on that metal? You should be inspecting the feed lips on all your mags regardless of what brand you're using.

Edited by d_striker
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Not to nay-say anyone's experiences, but I shot the recent Mid Atlantic Sectional match (300+ rounds) using factory SP-01 18rnd mags in a very dusty/muddy environment and never cleaned my mags (other than knocking them on my leg) and didn't have any gun/magazine/ammo malfunctions with my CZC SP-01 Shadow.

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Not to nay-say anyone's experiences, but I shot the recent Mid Atlantic Sectional match (300+ rounds) using factory SP-01 18rnd mags in a very dusty/muddy environment and never cleaned my mags (other than knocking them on my leg) and didn't have any gun/magazine/ammo malfunctions with my CZC SP-01 Shadow.

As I said before, I have been shooting those mags for over 15K without any issues until recently. The new ones are alright. They get damaged at some point though. The spring replacement alone does not help

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