Our suppliers are struggling to get some items due to transport issues.
We have had these 25mm by 300mm long sprue cutter specially made from thin wall polished stainless steel. Being so thin they do not compress the sand but cut it cleanly. The plug of sand is removed from the tube by gentle knocking against a hard surface. Do not dent tube or it impedes cutting and sand removal.
After ramming up your moulding box you cut through the cope to the drag before opening the flask to cut the gates and remove the pattern.
We find it much easier to use than traditional tapered wooden sprues which can be a nuisance to ram the sand around.