I tried purchasing a rifle using my work permit which has my alien number,my drivers license, and sss?

im currently on process of getting a greencard and i do have my work permit and sss and DL...i just want to know if this will be a problem in the future since DOJ putt my PHEC or Background check on pending..i did it all in good fate and under the impression that im doing it legally...short story can i make the purchase? if not what will happen and how will this affect me my status?