If this makes it big, I'm half-expecting a cease and desist order anyway, lol.
Quick update on the lower, looks a lot tighter now that I'm able to measure angles and radiuses on it. The magwell and grip mount appears to be spot on, hope everything else is too.
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View attachment 15632
Another overlay of the M4 lower on mine, lined up with the pistol grip mount. The beaver tail on the XCR is recessed back more than the M4 lower, but that correlates with what I've seen in reality. Overall, it looks very closely lined up. I'm concerned that the pin for the trigger on the XCR appears to be more forward than the AR's. The XCR trigger pin is located on the center of that lobe that's above the mag release, but it looks like the AR's is just behind that lobe. I was hoping to just extend the height of the XCR lower and not worry so much about pin locations, but it looks like I might have to work with this.
View attachment 15630
Next step is to disassemble my lower and get those final dimensions. Once the pin holes are in, I can start printing out prototypes for fitness testing.
Kinda regretting not getting some aluminum before prices climbed up this month. Considering prices and how big plate stock are, I'm really considering on building two lowers at once from one plate stock; the lowers facing each other in a yin-yang, 69 position as I mill them out. It'll save a ton on scrap and let me have two cracks at the project, just in case.
The CNC machine I'm getting to mill this is the Shariff DMC 2; it's being held up due to shipping lead times but should be getting around to me within a month or two, so I'm not in a huge hurry to have the lower completely designed until then. And other than hole locations and fine-tuning of the shape and fitment, it's not much work left now.