I am new to the NFA game and I am preparing to complete my first Form 1 after completing my trust with 199trust.com.  My question is if I have to register the trust with the state and how I can find out the requirements for that?  I reside in Missouri.

You should ask in your Hometown Forum to be sure, but most states do not require any kind of registration of trusts...

Even in the states that registration there is generally little consequence for not registering.

SilencerCo started offering an EasyTrust not too long ago. I mention that only because their info should be fairly current.

This is on their FAQ page:

States in Which You Must Register the EasyTrust at a Courthouse:
Alaska, Colorado, Hawaii, Idaho, Michigan, Missouri, North Dakota

States in Which Registering the EasyTrust at a Courthouse is Optional:
Florida, Maine, Nebraska

All states not listed above only require the EasyTrust be notarized.

States in Which Notary Requires Witness:
Alabama, California, Delaware, Florida, New York, Louisiana

I did see that, but when I just looked up the statute for MO, I am seeing this.

http://www.moga.mo.gov/mostatutes/stathtml/45600000271.html

Registration of trust.

456.027. 1. The trustee of a trust having its principal place of administration in this state may register the trust...

So it seems that it is optional since MAY does not equal MUST or SHALL.

I am getting more clarification on this, but on the face of the actual statute, it does not constitute a requirement.