Rep. Mark Critz is about to unleash a $600,000 ad buy in his primary campaign in Pennsylvania’s 12th district , according to the website Keystone Politics.

Critz is locked in a heated Member-vs.-Member primary with fellow Democrat Rep. Jason Altmire.

Critz had about $465,000 cash on hand as of the beginning of this year. That would make this a substantial, all-in buy for Critz about a month out from the April 24 primary.

Roll Call rates this race in the general election as a Tossup.