I'm with vbaInet on this. You are copying records - the same values - and that violates the rules of Normalization. So, we're trying to understand your business requirements and why you are actually doing this because it doesn't make sense from a properly normalized database perspective.
Yes we understand your requirement but that's the wrong way to go about this. You shouldn't have the same records and the same fields in two separate tables.
Change the records to that table, don't insert it into another table.
Use a query for adding/editting to that table for that specific MaterialID. Run the query to filter the records. Then use the query as your form's Record Source.