First AR-15 build complete — lessons learned and what I’d do differently

Just finished my first AR-15 build and wanted to share the experience for anyone else planning their first build.

The Build:
– BCM upper with 16″ mid-length barrel
– Aero Precision lower
– Geissele SD-C trigger
– BCM BCMGUNFIGHTER stock
– Surefire M600DF light
– Total cost: ~$1,100

Lessons Learned:

1. Buy an armorer’s block. I tried to save $30 by not buying one. Lost an hour of frustration. Just buy it.

2. Torque specs matter. Castle nut, barrel nut, muzzle device — look up the torque specs and use a torque wrench. I under-torqued my barrel nut on the first try.

3. Upper and lower fit varies. Even quality components can have some play. This is normal and doesn’t affect function.

4. Take photos as you go. I had to disassemble part of my lower to fix an issue and forgot the order of assembly. Pictures save headaches.

5. Don’t buy a complete lower — building it is easy and you learn so much more about how the gun works.

What I’d do differently:
I’d spend more on the trigger from the start. The mil-spec trigger it came with was terrible and I ended up upgrading to the Geissele anyway.

Happy to answer questions for anyone starting their first build!