With this work with my rifle?

There are three key things that an AR rifle will have to have for this device to work with it.

• The device fits in the relief in the magazine well that sits above the catch, indicated by the arrow. It needs to be a minimum of 0.480 inches wide and the distance from the top of the magazine catch slot to the top of the lower in that area needs to be a minimum of 0.670 inches.
• The current device requires that you use the modified, mil spec magazine catch provided, full stop. If you are ok with this, then you should be good on this point.
• The pull tab on the device exists in the space between the magazine and the upper in the area indicated by the arrow. To date, we have only tested on mil spec uppers, as shown on the picture. However, we suspect that many, if not all, uppers have sufficient room here.

If you think you meet these three requirements, then it is very likely that this device will work with your rifle. However, the only way to really know is to try it. To make that easier, we have a sixty day return policy, so there is no risk for you. All we ask is that if you do find that it doesn’t work for you, please let us know a bit about your gear so we can let others know and save them some hassle.

At some point in the future, we plan on doing other versions of this device to work with other non-AR platforms, but that is some time off. Moreover, there are some other ways to design this device to behave and operate a bit differently than it does now. These designs may be interesting to those who currently manufacture quick acting take down pins and might be looking for a low profile, internally mounted device to pair with their system. We have also considered doing our own version of a quick takedown pin, but that is on the back burner for now.

With this work with my magazine?

We tested about ten different magazines from different manufacturers, some poly, some metal, and all worked well. If your magazines look like a standard or typical magazine, especially near the where the magazine mates to the catch, and is of the standard width, then we would expect that you will not have any problems with our device.

We also looked at the CompMag and, as near as we can tell, this device should work just fine with it. If anyone out there can verify this, please let us know.

With this work with my ambi mag release?

Probably not, at least not yet.

This device requires that you use the modified, mil spec magazine catch provided. If your ambi release can accommodate that, then we would say that the odds are pretty good. If it can’t, then they are pretty much zero.

If this device does well, then plan A is to eventually approach the manufacturers of these ambi releases and see if they would add the slot to their device that this device needs to function. From what we have seen, many if not most ambi releases could be modified to work with our device without impacting their operation. If you want to help make this process go faster, contact your ambi catch manufacturers and ask them to look into this.

Plan B would be to design our own ambi catch that does work with this device, which will take some significant time to do. However, with so many good options already out there already, plan A seems like the best path forward. Hopefully, if it is possible to collaborate with current ambi catch manufacturers to get this done.

I am in a jurisdiction that allows it and am trying to operate in stock/non-fixed magazine mode, but the device keeps locking the magazine in place.

It must be noted here that operating in stock or non-fixed magazine mode, meaning the device is disengaged from the magazine catch, is only legal in jurisdictions that don’t require fixed magazines. You must check the laws in your area to determine whether or not this is permitted.

The fix described below may only be legally attempted in jurisdictions that do not require fixed magazines. Doing so would be violations of both the terms of the sale and the law.

This problem may appear to be happening when you fire the rifle. However, it is much more likely that the device moves and engages the catch before that, when you close the action on a new magazine. In our testing, we have never seen the device switch from disengaged to engaged as a result of firing, but have seen it occasionally happen on a new install when the action is closed on freshly loaded magazine.

What we discovered is that the tab on the device that has a small bend on it that can get bent a bit too far during the manufacturing process. This causes the tab to get caught on and dragged by the upper as it is closed. The result is that the device engages the with the modified magazine catch.

This fix is to bend it back or flatten it a bit so that the tab fits better between the upper and the magazine when the action is closed. This may take a few attempts to get just right. You can test whether it is formed correctly by setting the tab on the device in the ‘up’ position, loading a magazine and closing the upper. The device should not engage the magazine catch on closing and the magazine catch should release the magazine without issue.

Please review the video as to how to straighten this tab out a bit, its pretty straightforward. When finished, it should have just a very slight curve to it as shown in the video and images. The first image shows one with just about a perfect bend and the second shows one that has been bent too far. While the video shows this being done to a uninstalled device, you can do it to an installed device with the magazine and upper removed.

If you can verify that this problem is not happening when you close the upper on a new magazine but really is happening when you fire the rifle, the device may be defective. Please contact Cal Mag Fix to discuss the problem and possibly for a replacement or refund, if necessary.

The tape or glue is not holding the device in place.

The tape that comes with the device should create a permanent bond that holds up very well over time, if installed correctly, and it should work well for most folks. The super glue provided should provide for a rock solid bond that that is incredibly strong and very permanent.

If you are having a problem with getting either method to bond well, is usually a problem with the magazine well being dirty or oily prior to installing the device. While we do provide an alcohol wipe to assist in cleaning this area, it may be that the well needs to be cleaned more vigorously than the alcohol pad is capable of on its own.

In these cases, we recommend cleaning the magazine well, particularly the recess indicated in the photo, with bore cleaner, followed by warm soapy water, a warm water rinse and finally a wipe down with alcohol or acetone. If you do use acetone, make sure it is 100% acetone. Many nail polish removers have oils added into them and that will leave a slight reside of this oil behind. Do not touch this surface with your bare fingers after it has been cleaned.

If you are reinstalling the device after a failed install or after having removed the device, any tape reside must be fully removed from both the magazine well and the device itself. Both acetone and WD40 do very well with this, with the acetone being a bit better. This process for cleaning up the adhesive reside is covered in the first part of the section covering a glued-in install on the install page. After removing the reside, please follow the cleaning process listed above.

For the tape, it is also essential that the installed device be held in place, under pressure, for at least 48 hours. We provide a spring with the kit to accomplish this, but a small C clamp could be used in its place. The process for this is fully described in the install instructions and is also shown in the video here.

While a quality adhesive tape is used on the device and it is rated as a ‘permanent adhesive’, we definitely recommend that you do a fully permanent, glued in install once you are comfortable with the device. The instructions for this can be found on the install page.

The device migrated while the adhesive tape was curing.

This is the result of the spring, used to keep pressure on the device while the tape cures, not being aligned properly during the install. You will need to remove the device and reinstall it, paying careful attention to making sure that the spring is positioned so that it is not exerting an upward force on the device during the cure. Securely taping the device in place prior to loading the spring into the magazine will with also help with this problem.

These processes are covered in the install instructions and shown in the videos here. Additional information about removing the tape residue from both the magazine well device can be found in the first part of the section covering a glued-in install on the install page.