Abstract: A dual piston alternately reciprocating pumping apparatus utilizing, in part, a pressure based precompression stroke to provide product at a substantially uniform discharge pressure. In operation, a first feed piston is advanced through a first feed cylinder to discharge product therefrom, during which time a second feed piston is retracting within a second feed cylinder to obtain a product charge therein. The second feed piston reaches bottom dead center and thereafter advances through the second feed cylinder on a precompression stroke, during which no product is discharged from the second feed cylinder. After a predetermined pressure related to that within the second feed cylinder is detected, further advancement of the second feed piston is terminated and is not reactivated until the first feed piston nears top dead center. Therefore, a product having a substantially uniform discharge pressure is provided.