Longevity, Accuracy Tips for the AR15

[customcutter]

Thanks guys. Sounds like .998" it is then. I was hoping to avoid buying or making one but the earlier post about having to lap a CMT upper has me concerned now. I'd rather make parts, tools, etc, when I can. I'm not a machinist, but I have lot of machinist tools and it helps me learn more skills when I do "make" something. I'd take a class, but the closest one is 50-60 miles one way and $4500 a year. I just can't justify it.