There are a few possible explanations for the spelling of the word "shuntgun", which does not appear in standard dictionaries. One possible interpretation could be that it represents a dialectal or colloquial pronunciation of "shotgun", with the "sh" sound replacing the "sh" sound in "shush" or "sheep". In IPA, this could be transcribed as /ʃʌntgʌn/. However, without more context or information about the source of the term, it is difficult to say for certain what the intended spelling or pronunciation may be.