How wide is the upper paddle on the centered version? I ask because some billet / heavy upper receivers are thick enough that they have (and need) a cut-out for the bolt catch. Wondering whether yours will fit….
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0.528. The cutout on uppers doesn't present an issue, never has since ABC/R's introduction in 2015, as its upper paddle is angled outward at 5 degrees in the lower 50% of the upper paddle, and 9.1 degrees in the upper 50%, the TDP upper paddle cutout serves no purpose for ABC/R as its upper paddle doesn't fit in it at all, it's just a visual thing.
With some uppers like Mega/ZEV, the cutout looks as though it was made for ABC/R v3 rear biased version, though we didn't do that on purpose.
V1's upper paddle already clears all the uppers in 2015. In 2018 with v2, the upper paddle is thinned down and tapering towards the top, creating even more clearance between the upper paddle and the upper.