Quote Originally Posted by RCCrawler View Post
Ok, here's the scoop, I called the ATF Branch in Denver and asked the question.

-If it is a temporary change and you can change it right back, nothing is needed.
-If it's a permanent change you need to send a letter to the ATF NFA branch office listing your make, model, serial number, new barrel length, and new overall length.

He did not know if you could make the changes then send the letter, or if you had to send the letter first then wait for approval to make the changes so he gave me a number at the NFA branch to call.

The lady at the NFA branch said that you must send the letter, then wait for a response letter back from them before making any permanent changes. She said currently the wait on letters such as that is 3-6 months.
The Denver branch is LE, not technical side of things. While they can render a "guess" as you found out they are not savvy on NFA items. Unless you're in a sting.
If it's not from the tech branch back east, in writing, don't base what you do, on that answer.