New Build Problems

[Bigfuzzy]

I am new to building AR's. 1st build everything went fine, gun cycles & shoots as it should.
2nd build I upgraded to nicer parts(?). when it goes to battery it shoots fine. the problem is
it will not complete the cycle. it fires, ejects, then it stops about 3/8" from completing the
cycle. any ideas where to start looking or whats wrong with it?

 

[Clicker]

What parts did you change in the upgrade?

Sounds like a gas issue, I'd check the gas port size, gas block for alignment with the gas port and the gas key for proper fit to the carrier & staking.