Have you seen these swaddle wraps before? It's a one piece cloth that has a deep pocket where you put your baby's legs and butt in, then it has 2 long flaps that look like wings which you wrap around your baby with the attached velcros. It's super tight and comes in different sizes.
I got 2 from my sis-in-law and it's available online too.
It's quite useful if you are not too good at swaddling your baby with a muslin wrap. Babies tend to sleep better when they are swaddled tightly because it resembles back when they were in their mummies' womb, all tight, snug and cozy. It gives them a sense of security.