This is a remake of https://www.thingiverse.com/thing:6497903

The Openscad script is tailored for the Snowpeak PP750 or PR900W Gen 2.
Just select the following: the gun type, pellet diameter, number of shots, 3d printer tolerance, on which side you want the grip, align the grip to the bottom, add an alignment edge, add a magnet and magnet dimensions. For me the best settings are: grip on right side and with a magnet. This allows to keep the gun in your left hand while you use your right hand for reloading the magazine.
All is tested with a pellet of 4.5 mm (.177) and 5x2 mm magnets from Alie.
All sizes are in the metric system.

Without a pellet, loading the riffle/pistol with the magazine should feel the same as with the single shot tray, so WITHOUT forcing !! Some very light finishing with a flat and round file seems almost inevitable. Testing starts with pushing a pellet through the magazine with a (wooden) toothpicker. The pellet should NOT fall through the magazine but should, with some soft presure, slide through the magazine. If needed use a file to gently widen the hole. Next try it in the gun without pellet. Then if needed gently file the bottom flat.

The magnet can 'suck' the magazine into place which may result in that it slides over the perfect position. To prevent that use an alignment edge for the PP750 and don't align the grip to the bottom for the PR900W. The magnets are 'fixed' to there location with a drop of glue. Functions nice even with a 3-shot magazine.