Got some issues.....

[Cason76]

I have a stock DPMS 308, works fine, never had any issues for over 6 years. 

Recently I thought it would be fun to replace the stock 16 inch barrel with a DTT Customs "Break Point" LR-308 Featuring Aero Precision M5 Upper 20" Ultra-Match .308 WIN Stainless 1-10T Heavy Barrel 19" M-Lok Handguard, and a Fail Zero BCG. Now it will only eject the spent round and slam home without loading a new round in the chamber.

The BCG works just fine on the 16" barrel, and yes it was well lubed. Using Remmington core lock 180gn, and on occasion some reloads, 180 grain boat tails with 41 grain H11 powder. 

On the 20" barrel it will not lock to the rear with magazine inserted on last round, it will lock to the rear if done manually. The chamber is clean, the barrel is clean, the gas tube is clean and free of obstructions. Not sure what to do.

[sketch]

give us  link to what you bought..Dtt costoms? 

[392heminut]

Sounds like that barrel may have an undersized gas port! Not uncommon in this platform.

[98Z5V]

Sounds like DTT is Delta Team Tactical...  made from 100% blem parts from other companies, is what they do.  What's the "blem," though?  Is it cosmetic, and doesn't affect function, or is the blem a functional issue?  You never know.

Edited December 5, 2019 by 98Z5V