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The buffer assembly


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Hello forum,

I recently found a nice M1 Thompson for sale and I have begun the process of buying it. I have been picking up all kinds of accessories for my gun, but I have a question about the buffer. I picked up a NOS buffer, just for my collection, but I realize these parts are over 70 years old. Does anyone make a new buffer for these guns, or is it ok to just pick up a few of the buffers to act as spare parts, just in case one fails?
Thanks,
Mark

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The "buffer" doesn't actually do any buffering with it's solid rivets, I cut the buffer in half and remove the rivets and hard red rubber and cut a piece of urethane to stick back inside. No rivets are necessary to hold it all in place. Gives a much better cushion to the recoil impulse.
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This is one of those things that everyone talks about but has never occurred. I have posted a few times in the past requesting anyone who has cracked their upper receiver to post pictures of the failure and none have responded. Sure it could happen theoretically but as above "They made things right back then"

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Original AOC buffer assembly on the left, AOC assembly with rivets drilled out on the right

 

lxnD57Tl.jpg

 

What a disassembled AOC buffer assembly looks like.

 

xq05oisl.jpg

 

Pieces of buffer material ready to be sandwiched between original metal pieces. Material courtesy of MGB member john

 

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Side by side of original AOC buffer and a better "mousetrap" buffer assembly

 

WThbB97l.jpg

 

I don't believe that an original buffer assembly buffer does much to buffer but does a great job of holding the buffer pilot. The red material sandwiched and riveted between the steel outside appears to me to be the same material the WW2 1928 round buffers were made from.

Edited by Bridgeport28A1
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That urethane material is .100 inch or so and Ross is using two layers, as I've used as buffer material in my 28's.

Total thickness for two measures .200-.204. and durometer measures at a hardness of 80 A.

Ross will confirm it's really hard to cut and work with but not impossible, and is tough stuff.

I have several thousand rounds on one of my '28 guns with this material and the buffers still are in one piece.

Mnshooter yses one dusc fire and one aft if the pilots disc to avoid any steel to steel cintact and thats an option too.

With a machinist friend, we're currently working up a set of dies to cut these for '28 pilots and will keep the board posted.

Looking at this, I might give thought about this M1-M1A1 buffer as a worthwhile project for later this year.

Edited by john
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If the sole purpose of the "buffer" is to hold the pilot in place, then why make it unnecessarily complicated (rivets, different materials, etc.) on a weapon borne of a search for simplification (1928 vs. M1) A 100% metal piece would have done the same thing and been a lot faster to make.

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I appreciate the link but I didn't see an answer to the question. Perhaps because I'm looking for one based on a flawed premise.

 

Do the steel rivets compress upon impact?

If yes, then they + the red material work in unison to retard the reward motion of the bolt. So why not make the buffer out of one material that has the same overall effect?

If no, then they're acting like stand-offs in a circuit board and the qualities of the remaining materials are never realized. So what good do they do?

 

cbstmm_p_1_1.jpg

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The original WW2 M1/M1A1 buffer rivets do not compress. The hard red material in between the two steel pieces I do not believe compresses any. I could be wrong but simply believe there are better buffer materials then the hard red material.

Thus the reason PK sells newer material buffers and not WW2 vintage buffers for 1928 and his 21/28 hybrid buffer pilot.

PK also made a few M1 buffers, they used a modern material.

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Compress 1968 shotgun news pages in there coat with oil, & freeze. And you should be good to go.Make sure it had old ad from Curtis Earl.. he had great buffers.. oh wait guys that was his girlfriend.

 

This post made the internet today. ALSO DID colt MARK THE SERIAL NUMBERS ON THE FIRING PIN ORIGINALS ? off topic.

someone someplace in a far off land said they did? i miss Carlin he would have had material for the Thompson tales for decades.

 

okay back to the buffers, red blue screws or phillips wazz the magic? i like the green one. RON K.

 

SHOT SHOW will have the answers.

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The original WW2 M1/M1A1 buffer rivets do not compress. The hard red material in between the two steel pieces I do not believe compresses any. I could be wrong but simply believe there are better buffer materials then the hard red material.

Thus the reason PK sells newer material buffers and not WW2 vintage buffers for 1928 and his 21/28 hybrid buffer pilot.

PK also made a few M1 buffers, they used a modern material.

 

Then why manufacture & assemble a sandwich of 5 incompressible pieces instead of just making 1 big uniform equally-incompressible piece?

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It has to be of robust enough design to

 

1. Take the punishment of repeated impact and still....

2. Hold the buffer pilot in place securely through all that shooting vibration and stress

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My thoughts.....

These guns were designed and made for combat use. The goal was a reliable arm, not one that would last forever. With use and abuse, they will wear iut and parts will break.

The government could afford as many spare parts as it took to keep these running in combat.

 

But we're not in combat. In fact, the value of these guns now far exceeds the designers wildest notions.

So, why do I use a urethane buffer in the back of each of my subguns? Same reason I run them dripping wet with CLP......wear out or break that receiver and the fun is done. Even other parts are now so pricey it pays to protect them if possible. Many of us are trying our best to do all we can to keep from breaking what we have.

As such, many just shoot a few rounds and the gun becomes a safe queen.

 

Not me.

 

I bought these to have fun shooting and these small bits of urethane seem to prevent severe metal on metal impact and so I believe protects the gun from damaging wear.

I have one in my S&W 76, my Sten MkII and both '28's, as well as several 1911s and a few other guns I managed to adapt them to.

 

Just insurance, I guess.

from

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