Closed Bolt Full Auto Mini bolt, legal or not?

[badboy0757]

I've recently seen a couple CB-FA mini uzi bolts for sale. A friend and I are arguing over whether these would be legal to possess. His argument is they couldn't sell them if they weren't legal.:stick My argument is that it would be to easy to convert a semi auto mini uzi with one. I contend that these bolts are only legal to own if registered. Whose right?:grenade

 

[darkest2000]

Does the bolt have a blocking bar slot milled?

 

[emerz]

Does the bolt have a blocking bar slot milled?

Mini UZI bolts, semi or full auto were never manufactured with a milled slot, there is no blocking bar in a semi mini UZI receiver. And yes, it is fairly easy to convert a semi Mini UZI to FA, and HK's, and OB MAC's, etc.

 

[Kramer]

Mini UZI bolts, semi or full auto were never manufactured with a milled slot, there is no blocking bar in a semi mini UZI receiver.

Guys get so used to slots and blocking bars in the full size either don't realize this or forget that Minis don't have them.

 

[badboy0757]

Yeah, the blocking feature in a mini is the trunnion isn't cut for the FA open bolts feet. That's where this argument comes in. A FA-CB doesn't have feet and defeats the blocking feature in a mini. It'll drop right in and would only require the block in the lower to be removed to enable FA. No way the BATF would let this slide! I swear I've read somewhere that these bolts are not legal to possess. But I can't remember where and so I can't find it now.

I hope that someone who knows will chime in. As my friend is considering buying one of these bolts and I don't want him to get in trouble.

 

[darkest2000]

Learn something new everyday.

Mini UZI bolts, semi or full auto were never manufactured with a milled slot, there is no blocking bar in a semi mini UZI receiver. And yes, it is fairly easy to convert a semi Mini UZI to FA, and HK's, and OB MAC's, etc.

 

[shadeone]

I would like to know this as well because I would like a FA closed bolt as well as a full auto open bolt with feet since im an OCD mini uzi parts collector and need the complete set lol.
I do not posess a full auto lower without a selector switch blocking bar though so the "intent to construct" isnt there...

 

[shadeone]

anyone?

 

[badboy0757]

I have found out the BATF has recently changed their stance on a semi bolt with the full bolt face. So maybe these bolts would be legal to possess after all. Other than a few minor differences the closed bolt FA is the same as a semi bolt except for the full bolt face.

 

[TitleIIArms]

The Open bolt issue ( in this case ) Is they have feet and wont drop into a semi no matter what other mods u make. U would have to cut off or trim the feet way down YOURSELF to make these a questionable item. Then U have to face the bolt to allow the semi restrictor ring to clear ( or cut it down or off ) The closed bolt has the same restrictor ring clearance problem along with the other mods u would have to make to the lower.. These bolts are for people that own registered receivers or are building dealer samples.

 

[badboy0757]

Seems it would be a lot easier to convert a FA-CB to a semi bolt than a FA-OB. If these closed bolts were to be used in a semi build. What would have to be done to the bolt to make it legal? Would the lip have to be milled off? Would the bolt have to be clearenced for the restrictor ring? Or could the ring be clearenced for the bolt?

A lot of people bought these kits thinking they were semi's and these answers would help them out a lot. I've seen people convert the the open bolts into semi bolts. So it can be done. Seems it would be way easier to start with a closed bolt.

 

[TitleIIArms]

Bolt would have to be milled long ways from the front down to the face to open up the ID and it's HARD stuff. Cheaper to buy a semi bolt. I wouldn't touch the restrictor ring. It's put there for a reason.

 

[badboy0757]

On a FA-OB only a small portion on and near the bolt face has to be cut to clear a restrictor ring. Is the barrel channel in a FA-CB smaller?

I've spoken with several people who've converted full auto bolts. The two ways they do it are to either anneal the bolt first or use carbide tooling.

 

[TitleIIArms]

Ill take some good pics tom side by side.. I gotta go to bed now

 

[shadeone]

wake up! i want pics! hahaha
im a mini uzi knowledge vacuum and this topic intrigues the hell out of me!

 

[badboy0757]

I just spoke with the OP in the mini parts kit thread. He said the bolt in his parts kit clears the restrictor ring in his semi fullsize. I think some of the CB minis did use the restrictor ring feedramp. I measured my SA pistol bolt and the critical measurements are as follows: 13/16" across the barrel channel at the bolts front and boltface. Just shy of 2" from the bolts front face to the restrictor ring clearance cut.

His bolts face looks identical to my pistols. Except for the FA lip. He also said that there's plates welded to the top and side? My thought is that they were an attempt to add weight in order to try to slow down the CB's high cyclic rate?

1st pic is my SA pistol bolt. Other 2 are his mini bolt.

 

[TitleIIArms]

Well I took a couple pics side by side.. The IMI closed mini bolt vs Vector Semi. I dont really measure a lot difference in the ID between these two. The IMI SMG Bolt does seems to slide up to the restrictor ring and face of the trunion flush. I do measure a little deeper (.010-.015) from the front to face of breech on the SMG bolts but it may just be old to new design differences. The obvious differences are the full lip, lower slot on the bottom of semi bolt and the much larger ejection port on the Vector Semi.

 

[shadeone]

so do the smg closed bolts work in a semi? you mentioned they "slide up flush", but do they function?
if people start buying these mini kits it would be good to know if the smg bolts that come with could be used on newly produced semi receivers with restriction rings and only have to modify the lowers with a blocking bar...

 

[darkest2000]

My Bolt that came in the kit has the much larger ejection port as well as the lower slot on the bottom. It looks just like the Vector semi bolt that you have in the picture.

 

[TitleIIArms]

so do the smg closed bolts work in a semi? you mentioned they "slide up flush", but do they function?
if people start buying these mini kits it would be good to know if the smg bolts that come with could be used on newly produced semi receivers with restriction rings and only have to modify the lowers with a blocking bar...

Well I just ran a clip through a Vector Semi Mini.. Fires and cycles ( with help ) If u look at the rear of the older IMI bolt near the two top edges.. They are very square, fairly sharp corners. The Vector Semi Bolt has angled cuts running along the top about 3/16 wide. The IMI Bolt hangs up in the not so square Vector receiver when it cycles back. Sticks HARD in mine. Not a real big deal but the bolt would need to be relieved at those edges for it function in My Vector.