I'm actually impressed you figured all that out so easily lol When it comes to reinforced, the only spot I like to see thicker is the top rail above the cylinder, some cheapo shells hollow it out to use less metal and it gives me anxiety that it will crack. The rest is deadweight but it does help keep gear grease out of the compression area a little bit. Down by where the motor shaft is, the extra motor tower support is nice to have too. I'd much rather have a light aluminum shell, but besides for retro arms it's hard to get something of quality on the US market, there are a bunch of aluminum gelsoft shells I'd like to see over here. Who was first to make a "reinforced shell"? The only legit one is lonex with the front end and proprietary tappet to go with it. Some of the newer kwa shells are beefy up front too. Honestly I'm just happy my main gun works again. Kinda weird that I have a systema oem shell, always found their crap to be too simple to be so overpriced. I didn't know they could use a mold for that long before it has consistency issues. The retro arms shell also had various thickness all over sections that should have been consistent. Still mind blown you ID'ed this shell ha.