Going to is already future tense.
The future tense is: will get -- We will get some bread. am/is/are going to get -- We are going to get some bread. am/is/are getting -- I am getting some bread.
present tense and future tense
will future =will blunder going to future = going to blunder
The future tense of get is will get.
The future tense of "return" is "will return" or "going to return."
The future tense of "bite" is "will bite" or "is going to bite."
"Will spend" is the future tense of spend.
The future tense for speed is will speed.
The future tense of fling is will fling.
The future tense of scrub is will scrub.
The future tense of "crawl" is "will crawl".
The future tense of sweep is "will sweep" or "is going to sweep."