Sig Sauer MPX question (NFA or non-NFA?)

**tollster** · July 2nd, 2015, 05:17 PM

I need to pose a question to those that maybe familiar with the MPX-P and MPX-SBR.
The local dealer told me that id I purchased the MPX-SBR, which has the collapsible stock on it, it is viewed as a carbine, and falls un non-NFA rules. (I concur)

Then I ask about outfitting it with the telescopic stock, and was told if I change the stock out, it now falls under NFA requirements?

However, I am under the impression the MPX-P is non-NFA, and has no stock at all.

Can anyone clear this up for me? I know you require a minimum barrel length, but the MPX-P seems shorter without the stock, and the barrel length is the same as the MPX-SBR.

So I am not clear on why I could not put a telescopic stock on the MPX-P, and still have it fall under non NFA rules?

Perhaps the MPX-P is NFA?

Thank you.
Tol

**Gun** · July 2nd, 2015, 05:44 PM

If the firearm can be shouldered, and has a barrel less than 16", the firearm is NFA.

**forby** · July 4th, 2015, 08:24 AM

I suspect the dealer is passing a Sig MPX with a forearm brace as a non-NFA SBR. It's not an SBR according to the ATF(at least as of today). This could be why the dealer says that the pistol version BECOMES an NFA SBR when you add a "telescopic" stock(true) but the gun he calls an "SBR" is not an NFA gun with the other forearm brace stock.

Are you more confused now or less confused?

**codename** · July 4th, 2015, 08:18 PM

Originally Posted by forby

I suspect the dealer is passing a Sig MPX with a forearm brace as a non-NFA SBR. It's not an SBR according to the ATF(at least as of today). This could be why the dealer says that the pistol version BECOMES an NFA SBR when you add a "telescopic" stock(true) but the gun he calls an "SBR" is not an NFA gun with the other forearm brace stock.

Are you more confused now or less confused?

I would speculate the same.

OP: If we took the literal interpretation of you original post, a stock of any kind on a firearm with a barrel length less than 16" is a short barreled rifle (SBR) and is an NFA regulated item. The MPX-SBR as it is offered directly in SIG's catalog is an NFA regulated item.

It sounds like you should clarify what exactly the dealer is offering.

**ftownkev** · July 4th, 2015, 08:47 PM

I would also add that if the MPX-P has the Sig Arm Brace make sure you do not shoulder it like a normal stock. If you didn't know that ATF ruled that you are allowed to put the arm brace on a "pistol" but the moment it hits your shoulder it magically turns that "pistol" into a SBR and you are in violation of possessing a NFA weapon that is not registered with the ATF if you don't have a tax stamp for it and can get yourself into some big trouble. What that trouble is I'm not sure I have not heard of anyone getting caught for it but I'm sure the ATF will make a example out of someone to prove their point.