Uploading new pics as I am typing. If it makes any difference, I tried dropping a .270 round head first through the top of the barell and the round was too small, casing would go down the barell.

Next I tried a .30-06 round and it stopped about 1/8" before the casing starts. Stops about where it does on my Rem. 742 in .30-06, still I know there could be other possibilities..

Just want to be absolutely sure I have the right ammo before I go off shooting this thing. Especially my sister. Thanks for all the help so far!