Filler Material inbetween barrels

[B. Dudley]

I recently took apart a couple of sets of junk Parker barrels. One set had a tube blown out and the other set was cut short and badly pitted.

The one set was Parker Special steel from a 200,000+ serial Meriden gun. It had nothing between the tubes but 3 metal spacers that did not appear to be soldered in.
But, the other set was a earlier 10g. hammer gun top action set. When I removed the ribs, I found that the space between was fully packed solid with what looked like dirt or something. When I cleaned it all out, there was no serious pitting on the surface of the tubes, so it was not rust, besides, there would not be that much rust if it were.
Does anyone have any idea what this might have been? Did Parker pack the barrels with something to prevent corrosion? One Gunsmith I mentioned it to thought maybe cosmoline as he said it can dry out a look like dirt with heat and time.

[edgarspencer]

I believe they used a clay, much like babbit putty. It prevents the solder from continually flowing beyond the point it's needed, dramatically adding weight.

[Paul Harm]

I would think someone got in there and did their own " gunsmithing '. I had a set that someone had just about filled with plumbers solder.

[B. Dudley]

I have another uncut set from the same vintage I have to take apart. We will see what they have.

[Mike Franzen]

I removed the rib from an early 10ga set and found the same thing. My guess was it was some sort of heat sink to control solder.

[winplumber]

I had the same in my 0 grade hammer gun.