Glock MBX +2 Spring/Follower for 140mm (OEM Mag & +5 Base) Problems, Anyone Else?

[Brandon Breeze]

I recently started bringing one of my G34's out to USPSA Competition (Limited Optics) and figured I should try to have as many advantages as possible (don't we all).

Ordered up some of the MBX +2 Spring & Follower kits for a couple of my mags to test them out.

If you're unfamiliar, these pair with a 140mm length OEM Glock Mag that has an aftermarket +5 follower on it and will give you 2 more rounds for a total of 24+1, no lock back, reloadable (for me).

Obviously, we all know that 24 is better than 22! BUT I have been getting insane double feeds. Of course I had TWO double feeds in a row on the last classifier, so it absolutely tanked my score (frustrating).

Obviously 24+1 doesn't give you any advantage over 22+1 if it won't work

This hasn't happened every time I've used them, but it happened twice in a row during the last classifier and happened once before on another match.

Anyone else tried these kits and had issues? Were you able to get it sorted?

I'll try them a few more times, but will likely stick with the 22+1 mags for classifiers from now on.

 

[Jovanovic_Jardani]

I just ran the MBX +1 follower yesterday at a match. No problems throughout the day.

 

[Brandon Breeze]

I just ran the MBX +1 follower yesterday at a match. No problems throughout the day.

Appreciate the info!

Were you running them full at 24 round capacity?

I'm running mine with OEM Mag bodies and Warne +5 extensions.

Which extensions are you using them with, and are you using it with a Glock or another platform that takes Glock mags?

 

[RustVendor]

lol those are infamous for being bad, I like the csrg followers and springs.

 

[Brandon Breeze]

lol those are infamous for being bad, I like the csrg followers and springs.

I looked around quite a bit before ordering and didn't really see much in the way of negative feedback, so I figured no news is good news.

What setup are you using?

 

[RustVendor]

I looked around quite a bit before ordering and didn't really see much in the way of negative feedback, so I figured no news is good news.

What setup are you using?

I've used the csrg followers in my M&P and CZ for carry optics and LO. I don't do glocks so I can't say if they are good in glocks. If you look online there's a ton of people having issues with all of the MBX stuff from the followers to the magazines though so I haven't tried them. But I definitely only load the first magazine all the way up, if it's a reload it has to be downloaded one to give it room.

 

[2muchsoysauce4allthisrice]

I recently started bringing one of my G34's out to USPSA Competition (Limited Optics) and figured I should try to have as many advantages as possible (don't we all).

Ordered up some of the MBX +2 Spring & Follower kits for a couple of my mags to test them out.

If you're unfamiliar, these pair with a 140mm length OEM Glock Mag that has an aftermarket +5 follower on it and will give you 2 more rounds for a total of 24+1, no lock back, reloadable (for me).

Obviously, we all know that 24 is better than 22! BUT I have been getting insane double feeds. Of course I had TWO double feeds in a row on the last classifier, so it absolutely tanked my score (frustrating).

Obviously 24+1 doesn't give you any advantage over 22+1 if it won't work

This hasn't happened every time I've used them, but it happened twice in a row during the last classifier and happened once before on another match.

Anyone else tried these kits and had issues? Were you able to get it sorted?

I'll try them a few more times, but will likely stick with the 22+1 mags for classifiers from now on.

View attachment 220822

I have good results with agency arms, tti, and shield arms; since I prefer a hybrid of duty and defense based instead of competition based (tti is competition based), but have start using them at steel challenge practice. Havnt tried USPSA yet; only the practice bay. I havnt tried the mbx one you listed, warne, or the hennings yet.

I really dig the agency arms for the machined out overhang ledge on the side for slippery hands or possible fumbles.

 

[Blade]

Wait I’m new to uspsa shooting, why don’t you want all mags (3 for me) fully loaded? Also I’m running slr + 5 extensions and their power springs. sometimes I can load 23 + 1 is this a recipe for disaster for a malfunction? I had 3 my last match with my gun not going into battery. I thought it was my tungsten guide rod so I switched back to my OEM one. Thanks in advance!

 

[2muchsoysauce4allthisrice]

I recently started bringing one of my G34's out to USPSA Competition (Limited Optics) and figured I should try to have as many advantages as possible (don't we all).

Ordered up some of the MBX +2 Spring & Follower kits for a couple of my mags to test them out.

If you're unfamiliar, these pair with a 140mm length OEM Glock Mag that has an aftermarket +5 follower on it and will give you 2 more rounds for a total of 24+1, no lock back, reloadable (for me).

Obviously, we all know that 24 is better than 22! BUT I have been getting insane double feeds. Of course I had TWO double feeds in a row on the last classifier, so it absolutely tanked my score (frustrating).

Obviously 24+1 doesn't give you any advantage over 22+1 if it won't work

This hasn't happened every time I've used them, but it happened twice in a row during the last classifier and happened once before on another match.

Anyone else tried these kits and had issues? Were you able to get it sorted?

I'll try them a few more times, but will likely stick with the 22+1 mags for classifiers from now on.

View attachment 220822

I havnt tried playing with springs to get more rounds in.

If you want more rounds, but competition based, reliable, and shoot 9mm glock; how about tti? You can get 23+1 without needing to play with other springs, since it’s technically a plus 6 for 9mm, but loading it on a closed slide is not a smooth seat; you will need to ram rod it in there. If you want smooth load with slide forward, need to do plus 5 instead of plus 6. I’m guessing they were planning on people reloading with slide locked back.

 

[RustVendor]

Wait I’m new to uspsa shooting, why don’t you want all mags (3 for me) fully loaded? Also I’m running slr + 5 extensions and their power springs. sometimes I can load 23 + 1 is this a recipe for disaster for a malfunction? I had 3 my last match with my gun not going into battery. I thought it was my tungsten guide rod so I switched back to my OEM one. Thanks in advance!

Generally if it's completely full it's hard to get it to lock in when you are reloading fast. Not going into battery is often ammo related or recoil spring weight. What gun are you running?

 

[Brandon Breeze]

Wait I’m new to uspsa shooting, why don’t you want all mags (3 for me) fully loaded? Also I’m running slr + 5 extensions and their power springs. sometimes I can load 23 + 1 is this a recipe for disaster for a malfunction? I had 3 my last match with my gun not going into battery. I thought it was my tungsten guide rod so I switched back to my OEM one. Thanks in advance!

You'll need to be able to reload easily when the slide is forward and likely on the move. If you load the TTI to 23+1, this will be very difficult.

I havnt tried playing with springs to get more rounds in.

If you want more rounds, but competition based, reliable, and shoot 9mm glock; how about tti? You can get 23+1 without needing to play with other springs, since it’s technically a plus 6 for 9mm, but loading it on a closed slide is not a smooth seat; you will need to ram rod it in there. If you want smooth load with slide forward, need to do plus 5 instead of plus 6. I’m guessing they were planning on people reloading with slide locked back.

I have several TTI extensions, only one of them can get 23+1 without issue and still be reloadable. All the rest BARELY fit 23 & are hard as hell to reload with the slide forward. TTI likes adding 1 to whatever capacity you should really run the mags at honestly. Their 140mm 24+1 2011 mags are the same. Sure, you can load them to 24, but you're not going to be able to reload when you need to. I load them to 23. the 170mm sticks actually do 29+1 reloadable, so those are good, but not the Glock mags or other TTI's. Only time you would reload from slide lock in USPSA is if you didn't plan your stage very well.

 

[Blade]

Generally if it's completely full it's hard to get it to lock in when you are reloading fast. Not going into battery is often ammo related or recoil spring weight. What gun are you running?

Thanks for the clarification, I’m using a Glock 17. It could have been my ammo. I had 147 mixed with 115. Now I make sure to separate my range ammo and competition ammo

 

[john_marsten_1873]

I was moreso searching around for good quality springs followers rather than trying to inch out capacity. From what I've seen MBX is know for having issues yet still commonly used. I do have a few mags with MBX internals that have been running well but I don't push anything to the limit as I want reliability above all else.

It's gotten to the point where I'll run a stage here and there with a dummy round just so I can practice clearing malfunctions under pressure.

At the very least, use your most reliable mags for classifiers.

And yeah, down load 1 round on reload mags.

 

[RustVendor]

Thanks for the clarification, I’m using a Glock 17. It could have been my ammo. I had 147 mixed with 115. Now I make sure to separate my range ammo and competition ammo

I have some guns with tighter chambers that have issues with my 147 reloads unless I use a special crimp die and set them really short, definitely plunk test your ammo in the barrel you are using and see if that's the issue. I also see on your other post you are running an after market barrel, that could definitely be the issue I know radian barrels can be tight and do exactly what you are talking about.

 

[Experimentalist]

... I have been getting insane double feeds. Of course I had TWO double feeds in a row on the last classifier, so it absolutely tanked my score (frustrating).

Could you please elaborate as to the nature of your double feed?

The Glock magazines are double stack single feed. Only one round can come out at a time - at least in my experience.

How are two rounds coming from the magazine at the same time?

Thanks for the clarification.

 

[Brandon Breeze]

Could you please elaborate as to the nature of your double feed?

The Glock magazines are double stack single feed. Only one round can come out at a time - at least in my experience.

How are two rounds coming from the magazine at the same time?

Thanks for the clarification.

If I knew the reason, I wouldn't be making this thread, lol.

My theory based on what I saw it that two rounds are somehow coming out of the magazine. This did not happen before the MBX spring/follower, heck these 3 double feeds are the only double feeds I've ever even had with a pistol.

I was in the middle of a classifier, so of course we're talking rapid assess and remediate. First one, slide was stuck most of the way open with a round running right into the round that was in the chamber. Pull the slide back and lock it to dump the extra round and it falls right out. Shake the round out of the chamber since I didn't want to have my extractor fall on the round in the chamber, once the chamber was clear, hit the slide release to chamber the next round, chambers without issue. Pull the trigger, it fires, then blam another double feed where there was an extra round that came out of the magazine and was running into the cartridge in the chamber. Cleared that one the same and finished the stage.

GREAT malfunctions clearing practice, at the least fun part of the match

This G34 has a 13lb recoil spring, which runs well, but maybe is too slow?

 

[Experimentalist]

...I was in the middle of a classifier, so of course we're talking rapid assess and remediate. First one, slide was stuck most of the way open with a round running right into the round that was in the chamber. Pull the slide back and lock it to dump the extra round and it falls right out. Shake the round out of the chamber since I didn't want to have my extractor fall on the round in the chamber, once the chamber was clear, hit the slide release to chamber the next round, chambers without issue. Pull the trigger, it fires, then blam another double feed where there was an extra round that came out of the magazine and was running into the cartridge in the chamber. Cleared that one the same and finished the stage....

Thank you for the clarification, this helps quite a lot.

What you describe isn't a double feed. It's a Failure to Extract (or a "Type 3") malfunction, and most commonly shouldn't have anything to do with the magazine. As you already know, Failures to Extract are just the worst. Tap - Rap - Bang doesn't work as it might with the other types of failure (Failure to feed, Failure to eject).

I would speculate something has changed with your ammo and / or the extractor. I appreciate you were in a shade of a hurry and didn't pause to take careful inventory; it would be interesting to see what's going on with the cartridge case rim. Your description indicates there were additional rounds in the magazine. The follower had no direct interaction with what's going on in the chamber.

Here's what AI has to say on the matter: A Glock 34 failure to extract typically stems from optic mounting screws that are too long (binding the extractor plunger), carbon buildup in the extractor channel, a chipped extractor claw, or weak and underpowered ammunition causing short-stroking.

I would suggest first conducting a careful inspection of your pistol, paying particular care to inspect the extractor and related mechanisms, making sure you don't see any problems, including the above described issues. If that isn't conclusive then you may consider going to the range when there's no pressure, and send rounds downrange. When it happens, take careful inventory of the situation. Pictures can be helpful - you might bring a flashlight and a friend to help with that.

 

[Gawernator]

Never had an issue with my Walther PDP Pro mags ;P

 

[Brandon Breeze]

Thank you for the clarification, this helps quite a lot.

What you describe isn't a double feed. It's a Failure to Extract (or a "Type 3") malfunction, and most commonly shouldn't have anything to do with the magazine. As you already know, Failures to Extract are just the worst. Tap - Rap - Bang doesn't work as it might with the other types of failure (Failure to feed, Failure to eject).

I would speculate something has changed with your ammo and / or the extractor. I appreciate you were in a shade of a hurry and didn't pause to take careful inventory; it would be interesting to see what's going on with the cartridge case rim. Your description indicates there were additional rounds in the magazine. The follower had no direct interaction with what's going on in the chamber.

Here's what AI has to say on the matter: A Glock 34 failure to extract typically stems from optic mounting screws that are too long (binding the extractor plunger), carbon buildup in the extractor channel, a chipped extractor claw, or weak and underpowered ammunition causing short-stroking.

I would suggest first conducting a careful inspection of your pistol, paying particular care to inspect the extractor and related mechanisms, making sure you don't see any problems, including the above described issues. If that isn't conclusive then you may consider going to the range when there's no pressure, and send rounds downrange. When it happens, take careful inventory of the situation. Pictures can be helpful - you might bring a flashlight and a friend to help with that.

While I appreciate the thought behind your message, you (or AI) didn't follow.

This was not an FTE as the cartridges that came from the chamber in both instances were unfired, with no marks on the primer.

What I was describing is without a doubt a double feed.

This is what happens when you have a live cartridge in the chamber and another live cartridge right behind it. All confirmed when picking up the rounds off the ground after the stage was complete.

Ammo is Magtech 115g factory ammo and worked fine in my other firearm the entire day.

Nothing wrong with the extractor.

While I was in a hurry, I still saw everything that was going on, which is how I was able to clear the double feed, twice and complete the stage.

Here's an accurate visual representation of the malfunction I'm talking about in the OP:

From here, lock the slide back, remove the mag and give it a little shake, the cartridge in the chamber falls out. If this were an extractor issue and the cartridge were spent, the brass wouldn't simply fall out.

 

[Experimentalist]

I'm thinking a quiet day at the range will give answers.