Stuart Noble coughed up some electrons that declared:

I have tried one, and it progressively compacted the solids as you would
expect. IMO the only things suitable for such a device would be those
that normally come in a cartridge anyway, and they would be too sticky
to load manually.

I had a long look at those on the internet - I was wondering the same. Good
to have confirmation.

Gun delivery is certainly a good idea in principle - being able to inject a
fillet sized stripe direct to where it's needed without faffing.

But AFAICS, the only way this is actually going to work with with a pump and
a specially forumalated mix.

Some sort of electric gun (even something with a small battery drill on the
back) and a worm drive pump might work - thought I'd seen something like
that somewhere...

Tim