I wanted to share my experience for a first 308 build and say thanks to this forum for the knowledge sharing.
I didn't end up getting any video of the first shoot, and I really wish I would've now, but after all the threads and posts I've read I really expected some sort of failure that I would need to tweak. I was incredibly pleased when it shot (without bowing up), ejected, and racked another shell like a dream.. this will probably be a long winded post so I'm sorry in advance but I'm sure some people will enjoy a complete success story so I'll start at the beginning..
Aero Precision M5 stripped upper w/forward assist
Aero M5 lower complete (wouldn't have done it complete but I found too good of a deal to pass up)
Faxon 18" mid weight barrel
Aero BCG NiBo with exo coating
Aero charging handle (will soon be AXTS Raptor)
Radical firearms adjustable gas block (.750)
Strike Indus. Mid-length gas tube
Strike Indus. Comp/muzzle break
Next two things will be a Geissele 2 stage drop in & a Vortex crossfire II scope
Ok so again I'll admit this wasn't completely custom from the ground up but it will be by the time it's said and done.
After months of researching and reading and trying to locate parts/compatibility etc. I finally decided that I had gained as much knowledge as I was going to get without taking the plunge and learning from experience. One of the only issues I had with this entire build is parts availability and accessibility. After I got my receivers a fire was burning in me that I couldn't put out. All I could do was think about the next piece to the puzzle and I ended up building this entire rifle in 4 days. That being said I did maintain enough discipline to not sacrifice getting a part that I didn't want, and yes this was difficult and frustrating, but well worth it in the end.
To spare y'all from the boring parts of this build I'll just say each component fit together like a dream until I got to the barrel nut and gas system. From what I had read the threads on the upper need to be worked over multiple times when installing the barrel nut so I assumed this was going to be difficult without a vise before I even got started. To further complicate things this particular barrel nut has gas tube grooves that required it to be lined up absolutely perfect or the tube wouldn't fit into the upper. All I will say is if you have access to a vise use it and it helped that I greased the threads. The last part was the gas block and to be honest this was the area I was least knowledgeable about. I made sure I got an adjustable because there are other components that I will change and wanted to be able to fine tune it. I read that common practice was to close it off to start then slightly open it until it's smoothly ejecting and re-racking like you want it. I admittedly took a shortcut on this and guessed because I didn't have a whole lot of time that day and I got lucky that it worked out but will take the time to do it right the next time I go shoot.
Anyway for the happy part of this post, after getting everything fit just right it was time to make it go boom. I'd be lying if I said I wasn't nervous, anxious, excited, and scared shitless all at the same time. With adrenaline flowing I squeezed one off and she sang like an angel with my face still in tact!! I hummed a couple more through and she ejected and re-racked every shell without fail. I couldn't be happier with the end result and learned a lot from other people's mistakes on here so again THANKS to everyone who shared their issues, questions, concerns, and answers!
If anyone has any questions or would like some more detailed info ask away and I'll be happy to share what I do know and don't know!