Quick service announcement: How to model weapons in Blender.
Basically, you load a reference image into Blender and then you just trace the thing (in orthographic view), either (largely by extruding) with simple planes (faces, quads) or (in case of barrels etc) with something like a 16-sided cylinder.
And the parts that you traced with planes, you simply extrude into a three-dimensional shape so that they get depth. (You can round off the corners afterwards by adding some edge loops (Ctrl-R) and pulling those around in front/top view until it looks right.)
Slightly more difficult parts like this might require some elbow grease. Especially things like the holes. I believe I started with a cylinder for the lower part, then modeled one of the “wings” as just planes and extruded to create thickness. Then I probably mirrored that “wing” and positioned it on the opposite side, and finally connected everything. Luckily weapons don’t often contain terribly difficult shapes. (This part was done differently from the reference image because of possible copyright issues.)
The barrel and magazine tubes obviously began life as cylinders and just had some edge loops added and some parts extruded and connected.
This is high poly (subdivision) modelling, but since the parts were overall relatively simple, only a few control loops had to be added here and there to reign in the subdiv modifier. Once you get how that works, you’re set. The principle is always the same.
After this, either render to sprites or retopo and bake into a low-poly version as a normal map. Blender does support cage baking with Cycles, alternatively one could use something like Xnormal.
I hope this goes to show you that something like this is doable. I had done less than 10 weapon models before I made this. If you have any talent for sculpting or perception of proportions etc, you should be able to get the principle in no time. And then you just practice. Youtube has tons of tutorials for this as well.