Mix of NFA & non NFA uppers, lowers, rifles...whats allowed?

General Firearms NFA
1

I’ve recently acquired my first NFA device, an Ops 12th suppressor, for my Mk12 SPR and think I understand the basic NFA rules a little bit. .Looking to start down the SBR path. Here’s my situation now and in the foreseeable future:

I currently have 5 fully assembled AR’s (1:1 uppers/lowers) as well as one extra 16" M4 upper. I’m thinking that my first SBR would be a MK18 clone or near clone. I know I can either assemble it myself and go the Form 1 route or buy it from a dealer fully assembled as a rifle via a Form 4 (like my suppressor purchase). If I assemble myself, I have not made my mind up if I was going to register/engrave one of my existing lowers or buy a new one & LPK and build it all myself. Considering various MK18 uppers, but will probably buy a assembled MK18 upper vs. building the upper myself from parts.

So far, so good. But, here is where it gets sticky. What if I want to either buy a second SBR upper (say a 14.5" M4 upper) or take the existing extra 16" M4 upper and swap the barrel for a 14.5" one. How will this mix of fully assembled, non-NFA rifles mix and match in the eyes of the ATF with NFA SBR uppers/lower, etc?

  1. Can I have multiple SBR uppers (the non registered parts) for one registered SBR lower (follow process, get engraved, get tax stamp before SBR purchase, etc.)?

  2. If I go shooting, can I take the MK18 upper and the 14.5 M4 upper with me at the same time, along with the registered/engraved lower…or just one of the SBR uppers at a time?

  3. Having the mix of NFA and non NFA AR rifles/uppers/lowers in the safe at the same time…what guidelines should i follow and what combinations should I look out for as to not be in violation of the NFA?

2

As long as all the uppers you own can be used legally on atleast one lower you are fine.

If you have a short upper with no SBR or pistol lower then you are illegal.

If you have multiple short uppers and only one SBR or pistol lower, you are fine.

3

This is how I understand it as well. Obviously you can never install the SBR upper on any of your non-NFA lowers, but having multiple SBR uppers for one registered lower is not a problem, even if you have multiple ARs.

4

Thanks to both of you, that helps.

While I know you are supposed to report permenant changes to the ATF, swapping both SBR and non-SBR’d uppers on the SBR registered lower while at the range is not a problem right?

Or asked another way, if I purchased a 6th lower, followed all of the normal SBR processes to get it registered/tax stamp/engraving, etc…then I could use that lower with any combination of uppers (NFA and non-NFA) as long as I maintained the SBR upper configuation that I register it for on the Form 1, right?

5

Not a problem at all. Even the notification of permanent change is basically a suggestion. I guarantee the ATF doesn’t care if your gun is 19" or 21" overall, as long as it’s registered. Heck, most length info is an estimate anyway, as you shouldn’t have a complete gun to measure when you fill out your form 1.

I guarantee the majority of folks don’t amend their NFA info when they sell off a CTR stock and switch it out for an ACS, for instance.

Make sure you keep a copy of your paperwork with you, just in case some overeager LEO or range officer starts asking questions.

6

I would suggest not having a Title I (non-NFA) lower without a legal 16"+ upper on it at all times. Probably not necessary, but just good “insurance”.