Hi Capa M4 Adapter

thingiverse

The HPA file should fit an M4 magazine and mag catch with minimal modifications, allowing you to attach another magazine on top like a Hi Capa mag. First, let me start by saying this is a very intensive project. I used Vinyl Tubing, JB Weld, copper tubing, and an HPA tap to rig up a permanent solution to getting bb's from a M4 magazine into the hi capa mag. I found plastic was not the solution for me in this situation as it simply warped and made the part weak. 1. Find some type of tubing that feeds BB's smoothly through and will fit inside the M4 Mag lip. You will JB Weld this, or fix it into place in some fashion to allow BB's to flow smoothly through while disengaging the spring-loaded stopper. 2. I ordered Vinyl tubing on Amazon to connect the tubing from the M4 mag, into the tubing of the Hi Capa Mag. Ideally, this tubing connects both tightly, while allowing for disconnection when needed. 3. Now you need to find a tubing to fit inside of the Hi capa mag. You will most likely need to dremel out the bottom of the mag that leads into the BB chamber. This is done to maximize the amount of surface area for the adhesive to adhere to. 4. For a VERY important step, the tubing going into the bottom of the hi capa mag most likely must be bent. There are many crucial parts to this. First, the BB's must be able to flow through regardless of being bent. Next, your HPA quick disconnect fitting must fit alongside the tubing. Not to mention, if you are using a vinyl tubing and it sits high up, you will need to ensure it fits, or trim it afterwards. 5. Now with all these steps in mind, you are going to want to keep everything as SHORT as possible. The longer the tube for the BB's the travel, the less likely your mag will be able to push the BB's up all the way to feed. I am using a High Capacity mag, and would suggest you use the same as a Mid Cap most likely wouldn't have a strong enough spring. 6. Finally, this is an optional step, but providing some kind of support for your M4 Magazine is suggested as it will most likely bounce around without a support. The last picture features an earlier design with a support in mind.