u/excuseihavequestion

Hey all hopefully this is the best community to ask, just let me know if there is a r/ more focused on the Ishapore variants :). So I bought a used, sporterized Ishapore off of Basspro last year and ordered a magazine off Numrich. However, when trying them out at the range I could not get the magazine to seat even slightly, so I stopped trying and assumed I got the wrong type of mag.
Hopefully the pics of the markings, receiver and mag help but can anyone advise on what the exact issue may be? any feedback welcome!
exact mag I purchased - https://www.gunpartscorp.com/products/376330