Received my two 15-22 10rd LONG Mags yesterday.
Here's my instructions on how to convert them to 25rd mags. Sorry for the length of this post but I wanted to be as descriptive as possible. I didn't take any pictures...
First off, if you can find and order these, be sure to also order a set of these Raven Eye Custom loading assist buttons
There's 3 differences between the factory 25rd and 10rd LONG mags. One, there is a metal pin that prohibits the follower from traveling further than 10 rounds. Two, the follower in the 10rd mag does not come with a load assist button, however the hole is in place to be able to install one. Three, the followers are different colors. Other than that, the mags are identical.
So in my research on how to do the modifications, I found three generally preferred methods.
The first is to estimate where the pin is in the mag and drill from the sides to push the pin out. This results in holes in your mags. You have to be precise on where you drill or you'll be drilling extra holes.
Second one is to remove the mag floor plate and spring and then, using a long flat head screwdriver and hammer, carefully tap the pin to bend it until it falls out. Only problem with this method is that it could "bend" the plastic out of place when bending the pin. This could result in deformation of the track in which the bullets and follower slide up and down in.
Last method is to "crack" the magazine open by breaking the seal along the seam where the two halves of of the mag are glued together. This is the method I chose. If done carefully, this way results in as little damage as possible done to the mag.
So what I did to help make this as easy as possible was to nuke the mags in the microwave for 30 seconds. This warmed the mag just enough to soften the glue and make it easier to separate the halves. WARNING!!!! Ensure that you place the mag so that it "stands up" along its back seam. The pin will become very hot inside the mag and, if the mag is laying on its side or standing on the front seam, can melt the plastic around it causing it to deform the bullet/follower track or actually melt completely through the side of the mag.
Starting at the top of the mag use a sharp knife to pry open the mag along the BACK seam first. Slowly work your way down the back, carefully prying so to break the glued seam. Once at the bottom of the back side of the mag you will need to put the mag back into the microwave for 10-15 seconds to warm up the other side. Use something about the width of a marks-a-lot as a wedge to hold the back seam open and repeat the careful prying process on the front seam but this time start from the bottom and work your way up.
Once you have the mag split into two pieces you can now remove the metal pin. After removing the pin take the follower and slide it up and down the track. You will feel some "rough" spots. These spots seem to be made into the mag when casting it. Use some very fine grit sandpaper to smooth down those rough spots and any other spots you might have accidentally made in the mag when using the knife to pry it open.
Once finished sanding either blow the mag out or wipe it down with a damp cloth to remove the filings from sanding. You may have noticed that there's a "male" half and a "female" half. The female half has indentations where the male half has ribs that fit into it. Apply a thin bead of super glue to the entire seam area of the FEMALE side. Do not use too much glue or put glue on the male side. Too much glue can cause the plastic to melt and deform the bullet/follower track. Align the male side onto the female side and "snap" the halves back together. Use some rubber bands or some small wood-working clamps, if you have them, to hold the halves together tightly for at least 5 minutes.
Once the glue is set you can now reassemble the follower, spring and floor plate. When inserting the follower line its hole up with the larger hole at the bottom of the magazine. This is where you install the Raven Eye load assist button. Install the spring, ensuring it seats fully onto the base of the follower. Now compress the spring and install the spring plate and slide the floor plate back onto the mag.
You're done and now have a 25 round mag!