[[UM3] Extrusion issues with 3dSolex print core]

Hi there!

I just ordered a 3D Solex hardcore print core from gr5, and I have been having some issues. I've been trying to use the .8 mm nozzle and receiving issues with feeding material through it. When I start a print the filament just can't make it through the nozzle, and ends up getting ground away by the feeder.

Print settings:

.8 mm nozzle

.76 mm extrusion width

PLA

1.10 extrusion multiplier

.3 mm layer height

3 shells

4 skirt outlines

25% infill

60 C bed

205 C nozzle

cooling fan on

2400 mm/min print speed

Any ideas as to why this is happening? This is my first time printing with anything but a .4mm nozzle, so any help is appreciated. Thanks