sure as shooting vs surely

sure as shooting is an adjective but surely is not an adjective.

Word	Noun	Adjective	Verb	Adverb
sure as shooting	No	Yes	No	Yes
surely	No	No	No	Yes

As adverbs, sure as shooting and surely are synonyms defined as:

sure as shooting and surely: definitely or positively (`sure' is sometimes used informally for `surely')

Other synonyms of sure as shooting include certainly, for certain, for sure, sure, sure enough.

sure as shooting (adjective)	surely (adjective)
absolutely certain

sure as shooting (adverb)	surely (adverb)
definitely or positively (`sure' is sometimes used informally for `surely')	definitely or positively (`sure' is sometimes used informally for `surely')