When is your build deemed reliable? I am sure this has been asked before but its a hard search to word.
I have had a learning experience in building my first rifle and I’ve got it running well at this point. With ammo so expensive and hard to find I don’t have the luxury of running 500 rounds or more through it right now to determine if it is in fact GTG.
Thanks In advance
If it works when it has to, I’d say its reliable.
I ran two mags through it no malfunctions so I guess we will see. steel cased ammo in old rusty GI mag. Worst cased scenario really for food.
the cost to test a rifles function far outweighs the cost that malfunction could cost you…
I personally run a couple hundred rounds through new guns… try to push them pretty hard… before I really trust them… I had a 7in gun that I didn’t realize had a problem within the first few mags because the issue only materialized during high rates of fire…
I too run a couple hundred rounds through a new build. Get it hot, get it broken in, and see what stops working.
+1 on this recommendation
I had put a couple hundred rounds downrange in typical target shooting situation before I went to a class. Then it was 800 rounds in 2 days with no farts or burps. Yes, it’s a DD, BCM and Magpul combination so I was purty sure it would be OK. I’d bet my ass on it.
I dumped two mags through my m4gery with set screw held gas block, only to have the gas block grow and walk forward. Rifle stopped cycling, then the block cooled down and seized to the barrel where it’d been painted. I’m sure glad I found that out early, and not when it mattered.
Get it hot, keep shooting - see what breaks. 
Dumping 20 mags through it as fast as you can probably does more harm than good, but getting above a typical operating temp is needed to test things if you’re not 100%.
My pistol build did the same thing, only it kept working. The FSB was held by a single set screw and it walked forward before getting hung up. Now I’ve got a taper pin through it. GTG
Gas blocks really should be pinned. I’m pretty sure steel ones that are clamped are fine, but my set screw ones are getting taper pins.
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