Modifying the acoustics of a G&P rifle with memory foam

[MaciekA]

Some of you who have G&P rifles or have used G&P mechboxes (and possibly others who own full metal guns) have run into the phenomenon where the main spring "sings" for a moment after firing a shot. You can literally hear it vibrating, a bit like an ultra high frequency door stop. I think that some of the acoustics are attributable to the Aluminum construction of the shell and the actual body of the gun.

In my C8, I replaced the G&P stock with a Madbull T6 Aluminum stock, which actually increases the "cheek weld / ear report" you get from the mechbox via the stock itself.

I have an extra memory foam pillow my wife purchased and then decided right after purchasing was not the right fit for her. We have enough spare pillows for guests so I decided I'd take advantage of the dense memory foam in some of my side projects.

I've recently front-wired my G&P C8, so I had nothing but empty room in my buffer tube. After some experimentation I worked out the maximum slice of memory foam I could pack into the buffer tube without being unable to take it back out if I needed to access the spring guide screw.

The memory foam has a pretty dramatic effect on the acoustics of this particular gun, and the spring singing is non-existent. I've always been bothered by the sort of "empty metal box" sound that my G&P made stock, and this mod dampens that sound to a more pleasing "solid" one. I'm sure to readers of this post it probably sounds ridiculous, but some people who try it will almost certainly appreciate the change.

I'm going to experiment with packing the actual stock (it's one of those mod-stocks) and perhaps the upper part of the handguard with more foam just to see what kinds of effects it has on the acoustics.

I have not yet done any comparison recordings yet or determined whether the rifle is significantly quieter or not (I suspect it's more of a "change" than "attenuation").

Has anyone here experimented with this sort of thing?

[Kimbo]

I guy I played with about 8 years ago dynamatted the inside of his AUG and it was almost silent. Worked really well.

[ThunderCactus]

I use expanding foam to fill the stock of my VSR-10, makes a huge difference

[Amos]

You should replace the linear G&P spring with a non linear spring from Modify or equivalent brand... It'll get rid of that sound.

Also, ARS sorbo everything, proper shimming and piston alignment.

[Slow]

Originally Posted by ThunderCactus

I use expanding foam to fill the stock of my VSR-10, makes a huge difference

I have the same thing for mine. This will also creates perfect balance if done correctly.

[MaciekA]

Originally Posted by ThunderCactus

I use expanding foam to fill the stock of my VSR-10, makes a huge difference

Is this sort of foam generally non-removable ?

[Amos]

There's no reason to remove the foam in a VSR-10, the stock it just a big empty cavity.