Pump Mag Washer Specs

So I unboxed my Cerberus pump kit last month but couldn't find the wave spring or washer. Perusing AO I ordered Smalley wave springs, found a couple .220 spacers, and have the dimensions of the washer from HaveBlue ("the black bumper is 1/16" thick, 3/4" OD and approximately 0.465" ID") knowing I can always trim a blue bumper.

However, after talking to ManiacMechanic yesterday I learned that the black washer/bumper is more a hard plastic. A few searches brought up dozens of results but none specific as to the type of polymer used for the pump washer.

- Does anyone know what specific material AGD used for it?
- Has anyone ever found a replacement truer to the AGD-spec material?

Cut a blue bumper to fit inside the spring and you are fine.

Yup, cut a blue on to fit. Will work fine

I would like to disagree in the use of a cut blue bumper. I find that a cut blue bumper is far to hard. And has created cocking issues on pumpmags Ive worked on for other people.
I use uncut Clear RT bumpers and have for the last 17 years. Yes they were fast and do need replacing quite often. But they create a very nice soft pump stroke.

What are the hardness and material of the original bumpers compared to the pump kit ones and the rt ones?

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Originally Posted by captian pinky

What are the hardness and material of the original bumpers compared to the pump kit ones and the rt ones?

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I have a stash of original black pump bumpers. They are closer the the RT then the blue ones for hardness. I just always use RT ones because they are readily available.

I already cut down a couple blue bumpers but will do so to some clear bumpers as well.

Still hoping for more info on the factory black bumpers. It's interesting to note where the black pump bumper falls in the hierarchy of AGD-spec bumpers.

Quote:

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Originally Posted by Walking Stick

I already cut down a couple blue bumpers but will do so to some clear bumpers as well.

Still hoping for more info on the factory black bumpers. It's interesting to note where the black pump bumper falls in the hierarchy of AGD-spec bumpers.

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I have never cut a clear. I use them as is.