I know it can be done, I seen it, We had a young guy come to shoot trap and he shot quite a bit. I want to know if it is safe, I just bought a nice and tight Ithica made in 1901 and was thinking of playing with it.

It's NOT safe! the smokeless powder will still exert a lot more pressure than black powder. In 3 words-don't do it.

The older Ithacas and other shotguns of that era were not designed for modern shotshell pressures. I have two Ithacas (newer than yours by twenty years) and a Parker made in 1905. I shoot only low pressure shells that I load myself - pressures less than 7K psi.
I also shoot BP shotshells in one of the Ithacas. Those I load also.
BP shells would be kinder to you gun. Republic Metallic sells new paper hulled BP shells - the kind that gun was made to shoot.
BTW and FYI - "low brass" is not an indicator of power. Remington "heavy" dove loads are low brass; Federal's small game and dove load is a 3 1/4 dram Eq. and is low brass.

Pete