Hey guys,

I tried searching this question but wasnt able to find any real solid answers. In a few weeks I'll be filling out a form to register an SBR and at this point I'm a little bit confused as to which length to put on it. Lets say, to deal with round numbers, i want a 10 inch upper. Normally, in a non-ban state, i'd assume that you would just write 10" when it asks for length. Being in CT, and not having a pre-ban lower, i would need to permanently attach my muzzle device. The perm attached muzzle also counts as the barrel when counting length, correct? So would i have to put 11.5, assuming the barrel is 10 and the perm attached muzzle device is 2.1, accounting for .6 of overlap between the threads? I know what length upper i want, but having not bought one yet, i do not know what the TOTAL length of it would be to write down on my form.

So my question is, for a guy in a ban state like CT, what length would i write down on a form?

 

MP15T is correct.

However, if you're unsure which upper/muzzle device you want, I would simply put 10" on the form and send it in. Once it gets approved, you can notify the ATF of any changes that you make in the configuration. Notification isn't even required by law, but they do like to have it on their records. You don't have to maintain the configuration listed on the form, so don't worry too much if the lengths aren't exact.

in CT anything less than 12" is considered a pistol. and the laws pretty much make it impossible to make an AR pistol in CT. if you have a pre ban you can get around it but if not you need to be at 12". while less than 12" is perfectly fine with the ATF it is not okay with CT and our Assault Weapon Ban.

i'm planning on building and SBR here soon and plan on going with an 11.5" barrel and permanently attaching the muzzle brake to that to make it just over 12.5". from what i have read on here, the 11.5" barrel offers less wear and tear on the internals and gives about 100 fps more just because of that extra inch past the gas port. not sure if that is entirely true but numerous people on here claim it. also when you fill out the overall length on form 1 it is supposed to be measured fully extended but in our case it would be measured from te position that you pin it at.