McCallum has hailed the impact at West Ham made by Sam Allardyce.
He told whufc.com: "As a striker, I have got to keep scoring goals and hopefully I can get my chance in the first team and score a few goals for them.
"When Big Sam came in, everyone was saying that we'd play route-one, but it's not like that. The manager does like to play with a big centre forward and I have got to believe I can be that man - that if I get my chance, I am good enough to take it.
"Whatever happens - if I return to West Ham or stay out on loan - I want to keep playing well and scoring goals.
"If I get the chance to stay with Wimbledon, then I just want to be playing and making a name for myself in the Football League. If I come back, obviously I'll do my best for the Development Squad.
"The Under-21 Elite Group Stage is a big thing for the young players at the club. We won out first-stage group and now we want to win the Elite Group Stage."