I am piecing together a new AR15 upper and was planning to take it to a local gunsmith to have them assemble the components. I dont own a vice nor a receiver block and due to living conditions will have difficulties installing a vice. I may do one of those tricks of bolting a vise to a sheet of MDF and sit on the floor and use it that way.
What I am wondering is, when I read about AR15 uppers, I hear people complain that some backyard gunsmiths are assembling things wrong and overgassing or undergassing the guns. I assume that means when you insert the gas tube into the gas block that there's some configurability as to how much you install the gas tube over the hole in the barrel, and if you have it fully over the hole, then it might be overgassed, or if you partially block too much of the hole it's undergassed.
I'm not sure if it's something that happens when you assemble, or even earlier, like maybe how the manufacturer made the barrel and gas block?
I also plan to shoot suppressed, so I dont know if that means I need to configure it to be slightly undergassed, since the suppressor pushes back more gas. And if so does it mean the gun won't shoot as reliably without a suppressor on?
None of my uppers currently cause any issues either with or without a suppressor, but they were built by reputable gunsmiths. I did have an issue with one SBR not working well either suppressed or unsuppressed, I don't remember, and I changed the buffer tube to make it lighter or heavier (dont remember) and then it worked fine in either configuration.
I think I wound up having one of each of H, H1, H2 and Maybe H3 if that's a thing (somewhere in my closet of spare parts), which I got precisely for this kind of testing.
I'm just really curious how this all works and I don't trust googling it and finding some random youtube video because a lot of stuff out there in general is not reliable info.
Please correct my understanding of what I described. I assume if the gun is overgassed then using a heavier buffer will be indicated to slow down the cyclic rate to normal, and if undergassed then using a lighter buffer is better.
I have seen adjustable gas blocks but that seems like a gimick. Am I really going to insert some fine tool inside my rail MLOK holes to adjust a gas block if I take my suppressor off? Maybe but it seems like a hassle. And seems like a potential failure point. Also all 3 of my current uppers (11.5" to 14.5" have no issues going from suppressed to unsuppressed once I dialed in the buffer.