Question about barrel length/extra barrels on my LMT MRP SBR

[ShakyJ]

I have a registered lower for my 5.56 LMT MRP CQB SBR (10.5" barrel). I assume it is legal to buy a 16" LMT 5.56 MRP barrel and use it on this rifle? By doing so, I would be leaving the 10.5" barrel in the safe; I don't have another 5.56 MRP upper, so it could only be used with the MRP upper which is attached to the registered lower. Is it legal to switch between barrel lengths (10.5" to 16" and vice-versa) on a registered SBR? Also, would it be legal to have more than one 10.5" barrel for one registered rifle? For instance one 10.5" barrel with a Noveske KX3 and another 10.5" barrel with a smaller flash hider? Thanks for any help that can be provided.

 

[Aaron Baker]

Yes, you can put a 16"+ barrel on an SBR.

Yes, you can own more than one short-barreled upper for a registered SBR lower.

Just re-read your post, and it sounds like you're talking about swapping just the barrels. You may own entire upper receiver assemblies in the configurations discussed. If the LMT's lower is a standard AR15-style lower, you can put any AR upper on it that you want in any barrel length and caliber.

Aaron

 

[MasterSergeantA]

As Aaron said, yes you can. You may have as many barrels or complete uppers in whatever lengths/calibers you like for use with the SBR lower. The ATF would 'like' you to notify them if you decide to adopt a "permanent" configuration that is different from the one on your Form 1 or 4. So if it was registered as a 5.56/10" SBR and you decided that a .300BLK/12.5" was a better option and you wanted to keep it that way, letting the BAT-men know would be a reasonable idea. You would always have the option to switch back.

Having said that, unless you were to sell the 5.56/10" upper, no change would necessarily become "permanent" until then. And if you sold off all barrels/uppers shorter than 16", you could even notify them that it was no longer a SBR and the registry would be so noted. It could them be transferred as a Title I firearm.

Just food for thought.