Proper way to install a buffer to increase cyclic?


Feedback: 1 / 0 / 0
Jun 25, 2022
I got a couple of the hard rubber 1-3/4" semi-auto buffers from US Barrel Shrouds and used a band saw to chop them into shorter segments to boost the cyclic on my full sized Uzi SMG. Want to get it up to 850-900 rpm, so from what I've read a 1" block will probably work out best for me. I now have have 1/4", 1/2", 1", and 1-1/4" blocks.

However I am wondering what the proper way to install them might be. There is no helpful information about this that I can find on-line. Should they go in front of the U-shaped red plastic plate at the end of the recoil spring assembly, or behind it? Do I leave the plate on the recoil spring rod, or remove it and run the rod through the corresponding hole on the buffer? If I install it improperly, is there any risk of damage to the gun?

I'd love it if someone had close-up photos they could post of a correctly installed SMG buffer.

Dirk Hawthorne

Well-known member
Feedback: 0 / 0 / 0
May 22, 2023
Just slide the spring through the hole and call it good.

There is no good reason to remove the existing rear plate from the spring, it will just ruin the spring for regular use.

The rear plate will not change how the gun runs in any way that you would notice. I say that as someone who studied spring/mass oscillators at the graduate level.

Note that running hotter ammo will speed up the gun to a noticeable degree.


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UZI Talk Life Member
Feedback: 8 / 0 / 0
Nov 9, 2009
You can trim the plastic block with a thin bladed pipe saw to get the perfect rate of fire for you. My block kept moving around inside the gun so I used some jb weld on the top so it would fit snugly but I can still get it out to clean.

I don’t know what my rate of fire is but it smoothed the gun up considerably and made it a lot easier to shoot accurately but it does speed it up. Not near as fast as a Mac 10 but a lot faster than factory.

If you want me to send you a picture of my block just text me at two 0 five 9 one five 8 seven four 9.

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