1 kg Prusament spools may not fit in your AMS because the overall width of the spool is more than 68mm.

The root cause is not the cardboard cylinder (these are the same height for both) but the side panels. The ones prusament is using have a thickness of 4,5mm while the bambulab ones have 3,5mm. As the Bambulab spools are put together you always have a consistent width.

Using this adapter ring you can use your prusament filament in your AMS as you are using the intended dimensions of the Bambulab spools.

The adapter is designed to fit on both spool parts as they slightly differ in diameter.

Assembly for spools

Carefully disassemble the first side panel from your existing prusament spool. Put the adapter ring on one of the Bambulab spool parts. Push the Bambulab spool with the adapter in the cardboard cylinder of the Prusament spool. Repeat this process for the other side.

Always keep your filament tensioned so that you will not get a tangled filament.

Assembly for refill

I haven't tried this yet, but should work the same as the cardboard cylinders are the same.