SpudFiles

Wood dowel--- you could even tip it with screws for weight and sting.
Wrap the "slugs" w/tape to make it snug in barrel.
I've shot dowel slugs in my 1.5 " barrel wrapped w/masking tape.
Dowels come in all sizes .You could even put vanes on them.
On burnt latke they put a diaphram on the back of the slug to trap gasses and make them faster. The diaphram also centers the slug in the barrel to shoot straight.

in my experience 1" marbles don't shatter on hard targets as easily as smaller marbles. Maybe its just my gun, but I have put a 1" marble through over 10 shots at a brick wall, until it ricocheted into the "bushes of no return"
R.I.P. expanding metal anchor and countless marbles.

hot damn! i cleaned my room for 4 hours *ugh* and come back and this thing is 2 pages long. now i have to read them all.

thanks in advance, cause im sure ill get some good ideas.

EDIT: yes Frank, it seems that there is a phenomenon involving "bushes of no return" it would appear that they reside in the yard of every house in the world, preying on small, hard to find things. I myself have several of them, they claimed the life of a large neon green ball last year. probably the hardest thing to lose