We have a few prototypes that we have punished over the last eight months with 223 and 5.56 and haven't ever had to replace anything yet.
I don't see you having any issues at all with subsonic
I would love to see that video and be able to use it on the site.
I have a few customers that have their tax stamps and use the tubes with 30 calibers regularly, they haven't had one blow up yet but I couldn't honestly say that the max rating would be in regards to caliber size without doing some testing. I would probably want a titanium tube (coming soon TM) for anything over .30 caliber
In regards to what steps are needed for the Form 1, if you don't have one already I would advise you to create a multi-generational NFA trust then print your trust, sign your trust in the presence of a notary and two witnesses. The witnesses must be the age of majority and cannot be beneficiaries of the trust. The co-trustees do not have to sign any documents.
After completing those steps your trust is now a valid document similar to a contract or a will.
Scan your complete trust and use that to e-file for your Form 1 at
www.atfonline.gov/EForms
During the course of applying for your Form 1 you will need to choose a model name, serial number and caliber for the suppressor you will
make. The serial number should be at least 4 numbers. Since you are the manufacturer these can be anything you come up with.
Once that application process is complete you will just need to wait for your tax stamp, once you get it print it out and make sure you save it because you only receive one copy.
All that's left is to build out your Solvent Trap into a suppressor and engrave the following on the barrel:
Trust Name
City, State
Model Name, Serial Number, Caliber
For example:
XYZ Trust
Orlando, Florida
STS-01, 0192, 223
Once again, the model name and serial number will be whatever you created during the Form 1 application process.