Just wanted to shoutout a member, (Tango Sierra) for his excellent 3d printed mags. I purchased four .22 cal 12 shot mags from him for my new XM1 Bullshark. I am very impressed with them so far. More shots, easier to load, and they cycle much more smoothly than the factory mags. Shipping was fast as well. His website is www.bigairprecision.com and he makes many other mags as well. 
