MCK Micro Pistol Conversion Kits

When you attach your handgun to the MCK, does this make it an SBR requiring a tax stamp? There are so many differing opinions on this, all I have become is confused. I get the impression that it does indeed become an SBR. Yet, I see tons and tons of comments about people who have one. So many in fact, that I
find it hard to believe that many people shelled out $200 for a tax stamp. If anyone can clear this up for me, I would be grateful.


Welcome @Patrick202!

I’m not a legal expert on this topic.

I did do some research because I was originally interested in buying a kit for my Glock. Seems like you are ok with some models, but not others.

Pistol to rifle conversion does not require a tax stamp. So, if the kit’s overall length is over 26 inches then you should be ok.

For now, you can also get a kit that uses an arm brace because you’re not really changing how the firearm is designed to be fired - held in your hand.

The option to stay away from is a kit that uses a stock (folding, telescoping, or otherwise) with an overall length of less than 26 inches.

I’m sure there’s a lot of other variations to take into consideration.


Thank you! That info was helpful.


Welcome to the family brother @Patrick202 , glad you could join us. I also would like to know more on this subject.

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I believe the fact that the magazine is still inserted into the grip of the pistol keeps the mck a non nfa item…at least in that area. I’ve seen them on the wall at my lgs. Neighbor has one, I wasn’t impressed with it, had some fit issues that can be adjusted,but taking a simple platform like a Glock and complicating it isn’t for me.


Welcome to the family brother @Patrick202 and you are in the right place at the right time.

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Most of these conversions have braces instead of stocks which likely makes them legal (for the moment) in many places.

The big issue with these kits for Glock pistols is they have no way to secure the trigger when carrying. I don’t have an issue carrying a Glock without a safety in a quality holster. But I would never want to walk around with a long gun without the safety on unless I was ready to fire it. Might be better if they had a sliding or pivoting piece that would cover the trigger. Or guess you could carry it cruiser ready. Though suppose it could be less of an issue if it is just a bump in the night gun that you are only carrying when responding to an imminent threat.