What is the exact length of carbine and heavy buffers?

I have 3 buffers that all measured differently. My newest never used BCM carbine buffer measured at 3.270, my slightly used BCM carbine buffer at 3.250 and my Spikes T2 with 2k through it at 3.235.

I'm curious to what the actual length is, I tried to look it up online with no luck.

Does the rear plastic bumper ever mushroom out or wear?

Nominally the only difference between buffers is the composition of the weights inside. Bang rubber around enough and it starts to lose its "rebound," which sounds like what your older buffers are showing.

I'm not in a position to do this, but it would be interesting to take a known "correct" virgin buffer, and run it through several thousand rounds miking the length at regular intervals of say 250-500 rounds or so.

For what it's worth:

Bonus Tip: Select a proper buffer
Selecting the rifle buffer is simple: there is only one. Except for the very earliest buffers, there is just the one rifle buffer: six inches in length.


For the carbines, there are a host of buffers, and one in particular is to be avoided. The shorter carbine buffer lacks the second spring shoulder found on the rifle buffer. Some of the carbine buffers can be found made of a plastic moulding instead of machined aluminum. These will be filled with lead shot. While they weight much the same as the proper aluminum carbine buffer, they are a cause of unreliable function. A carbine containing this buffer should have the wretched plastic abomination exchanged for a proper buffer.

A cutaway carbine buffer weight, showing the internal weights, the spacers and the plastic plug.
The proper ones are made of turned aluminum, 3-1/4 inches long, with a nail-like head and a plastic tip.

https://gundigest.com/more/how-to/gu...recoil-springs

Quote:

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Originally Posted by bamashooter

For what it's worth:

Bonus Tip: Select a proper buffer
Selecting the rifle buffer is simple: there is only one. Except for the very earliest buffers, there is just the one rifle buffer: six inches in length.


For the carbines, there are a host of buffers, and one in particular is to be avoided. The shorter carbine buffer lacks the second spring shoulder found on the rifle buffer. Some of the carbine buffers can be found made of a plastic moulding instead of machined aluminum. These will be filled with lead shot. While they weight much the same as the proper aluminum carbine buffer, they are a cause of unreliable function. A carbine containing this buffer should have the wretched plastic abomination exchanged for a proper buffer.

A cutaway carbine buffer weight, showing the internal weights, the spacers and the plastic plug.
The proper ones are made of turned aluminum, 3-1/4 inches long, with a nail-like head and a plastic tip.

https://gundigest.com/more/how-to/gu...recoil-springs

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So 3.250 is the length? Is they're a +/- range to that?

Proper length of a carbine buffer is short enough to allow bolt to lock back and long enough to keep the gas key from striking the receiver extension, there is a range in there but as long as it does these two things it is the "proper length".

Quote:

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Originally Posted by SHERWINVILLARETE

So 3.250 is the length? Is they're a +/- range to that?

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The aluminum body is usually uniform in length from part to part. The length of the nylon tip varies. They also flatten over time, especially when the AR is over gassed