I may have made a mistake on my Form 1.

Here was the plan: It was my intention to make an 9mm SBR out of a AR-15 lower using a 3-lugged 5" barrel covered by a free-floating hand guard that extends beyond the muzzle. I intended to attach a suppressor to the three-lugged barrel so that the fore end of the suppressor extends 3 inches beyond the front of the hand guard. As there are no instructions offered by the NFA Branch of how to measure the "overall length", I stated, well, the overall length, with the butt stock fully extended (not including a suppressor of course, since that is a separate firearm). I was latter told by a person who I consider to be an expert in these matters, the overall length should be measured from the muzzle back to the end of the fully extend butt stock. That made the new "overall length" a good 7 inches shorter than what I had stated on my Form 1.

By then, my Form had already been in the hands of the NFA Branch for one month, or so I thought. So, I wrote them a letter explaining what I had done with the hope of getting either a letter in return acknowledging the new measurement or one that informed me that the measurement I stated on the Form 1 was actually valid. A little over three months after I sent the letter, I called the NFA Branch only to learn they didn't have receipt of the letter recorded in their log. I am guessing they do actually still have it though.

All the same, I am going to resend the letter because maybe I did not use the correct wording and as such the letter was ignored. Does anyone have an example of how to word a letter like this?

And I am also interested if anyone thinks I may have actually stated the overall length correctly.

Thanks.