Have you actually experienced stress cracking? I used epoxy because that is what I had laying around. I call this my S--T LAYING AROUND project (SLA) because literally, it is made almost entirely from what I had on hand. The only thing I purchased was some fastenings to assemble the receiver, forend and mount with. I'm a welder by trade, lots of scrap aluminum laying around. The similarity is that schd 40 aluminum pipe is 6061. I understand about the heat, I never have shot more that 20 rnds in an hour. My choice for the filler was originally to be an aluminum filled polyurethane from PolyTek. Very low shrinkage and good bonding. Fun talking, and as I stated I understand not revealing proprietary stuff. Like I said, that's why I have a sock over my recoil device!
