There’s really no way to advertise your faction and/or grow it substantially without a discord. I’d also recommend, once you have a minimum of 30 members, submitting your faction to the Shiguto website so that it becomes an official faction visible there. There’s no penalty for not having an approval for your faction, but it really does help to have a discord and such.
It’s no problem, I’m more than a bit of a gun nerd and I like to output my random knowledge. If you’re looking for a silent and heavy weapon, try the OTs-38, a 7.62x44R integrally suppressed revolver. More than enough of killing power.
The gun is based off the Heckler & Koch MP5SD, the integrally suppressed version of the MP5K. So your “M191A1” (which I was not able to find, so I’m going to assume you meant an M1911A1) isn’t going to be replaced by this gun. The MP5SD is an integrally suppressed, select-fire 9mm para Machine Pistol, while the M1911 is a self-loading .45 ACP pistol. It’s not going to be replacable.