How do 9mm holes prevent using SMG lowers?

[OPinOKC]

From the Uzitalk library:

Large Trigger Group Lug/Pin:
All the semi automatic UZI's have a 9mm hole in the trigger group lug that is welded on the bottom of the receiver, and a 9mm pin that goes through the trigger group and the lug. This is to prevent installing an SMG lower (which have 8mm holes) on a semi receiver.

I don't understand how the bigger SA hole keeps you from attaching an SMG lower. My (FA) Uzi has a 9mm hole, but I can attach an SMG lower with its 8mm pin and it feels like it's in there solidly.

OP

[RoverDave]

Yes, you can attach it but the lower won't be held in the proper place so the sear/bolt contact will be wrong.

[shadeone]

also, why would someone go through the trouble of putting a bushing/welding the hole on the receiver to make the lower work instead of just enlarging the hole on the lower to 9mm? seems like more work?

shade

[RoverDave]

also, why would someone go through the trouble of putting a bushing/welding the hole on the receiver to make the lower work instead of just enlarging the hole on the lower to 9mm? seems like more work?

shade

Changeing the receiver brings the gun in line with regular SMG specs so you can freely drop on different lowers without changing each one. Also, if you have the correct bushing available, it's less prone to error. Drilling the lower off center can cause problems.

[shadeone]

any source on the bushings? I want to use an proginal "ARS" lower with my gun when i get it redone (with blocking bar of course!)

shade

[Glockdude1]

From the Uzitalk library:

I don't understand how the bigger SA hole keeps you from attaching an SMG lower. My (FA) Uzi has a 9mm hole, but I can attach an SMG lower with its 8mm pin and it feels like it's in there solidly.

OP

If the SMG sear is in the lower, the lower will not fit all the way on. The SMG sear will block the lower from being able slide into the bushing of the receiver.

[Nighthawk1975]

Why open up the holes to 9mm in the lower or use an 8mm bushing in the receiver when you could just replace the internals of the SA lower with the ones from the SMG lower?

[Glockdude1]

Why open up the holes to 9mm in the lower or use an 8mm bushing in the receiver when you could just replace the internals of the SA lower with the ones from the SMG lower?

Yes you could, BUT, it would NOT be legal AND the lower would NOT go back on/into the semi receiver. The SMG sear pads will NOT clear the semi-auto sear pad holes.

Now you can use a SMG lower on a semi, IF a blocking bar is welded to the inside/front of the lower. Even if you did manage to use a SMG lower on a semi, it still would NOT give you full auto fire. The gun would jam right after the first shot.

[Nighthawk1975]

Yes you could, BUT, it would NOT be legal AND the lower would NOT go back on/into the semi receiver. The SMG sear pads will NOT clear the semi-auto sear pad holes.

Now you can use a SMG lower on a semi, IF a blocking bar is welded to the inside/front of the lower. Even if you did manage to use a SMG lower on a semi, it still would NOT give you full auto fire. The gun would jam right after the first shot.

I wasn't saying that installing SMG components in a semi lower would turn a semi to full auto. I was only stating that if a class 2 was converting a semi to full auto he could install the SMG parts into a semi lower after removing the blocking plate to avoid using a bushing or enlarging the 8mm holes along with the rest of the process of converting. I was just talking about there was a way around both the bushing and enlarging the holes to 9mm.

[Open Bolts]

any source on the bushings? I want to use an proginal "ARS" lower with my gun when i get it redone (with blocking bar of course!)

shade

http://www.home.earthlink.net/~landsden/index.html

Be sure to specify that you want an UZI lower bushing 9mm to 8mm (and NOT a trunion bushing)