M&P22 pistol mag loader mod for HKS 22S.
New member here, looks like time to jump in. I just modified an HKS model 22 S magazine loader (as shown above, and $3-5 everywhere) so it will work with M&P 22 pistol magazines. The HKS model 22 S loader for the S&W model 41, 422, etc. magazine has the correct side to side opening for the M&P 22 magazine, but is too tight front to back. Using a 3/8 inch wide triangular file, I opened the loader to fit my M&P 22 magazines, and it still works fine for my model 41 / 422 magazines.
The picture shows an unmodified loader on the left, and the modified one on the right. The inside of loader was filed in two places. First, the top/back of the loader was relieved to provide the additional clearance needed to start the magazine into the loader. Then, the front of the loader was "squared" to clear the magazine latch bump on the front of the M&P 22 pistol magazine.
Start with the rear clearance, at the top of the thumb rest. File it back to the top of the first step on the thumb rest, keeping it square on top but angled towards the inside of the loader. I hope the picture shows this fairly clearly. The loader has a projection inside on one side. It could probably be removed for M&P use only, but I left it in place. File a little, check fit a lot. The plastic material files cleanly but slowly. Use a wire brush to clean the file frequently. Relieve the back of the loader until a magazine can be inserted up to the magazine catch bump with light pressure. If it were not for the magazine catch bump, you would be done now.
Next, to provide clearance for the catch bump, the front inside of the loader must be filed square, or nearly so. I used the triangular file to avoid the little projection inside of the loader. With a magazine partially inserted, study the angles of the loader and the magazine from the side to see where to file, as nothing sets quite square. The front part of the loader is the thinnest stock to be filed. I cut that area deeper than I would now recommend, thinking I needed a fully square notch for the mag catch bump in order to get the right fit. A stronger approach would be to leave a little bit of the rounded portion showing in front, squaring just enough to clear the catch bump ears, and then remove more material from the thicker, thumb rest portion as needed to get the desired fit. Again, file a little, check a lot. I prefer a fairly loose fit so the magazine spring will push the loader up.
The tail of the loader is not designed to catch on the bottom of the mag base, it seems to provides tension and alignment. By the way, I am delighted with the M&P 22 pistol and its 9mm brother. Thanks to everyone here for their tips and info!
