Barnstaple accepted they were simply outplayed by a better team in their heaviest defeat of the season.
Bracknell scored nine tries to win 55-10 and move into second place in National League Three South West.
It was more than 20 points worse than Barum's previous heaviest defeat, 27-3 at Old Redcliffians in December.
Joint head coach Steve Perry said: "Bracknell were a very good side and played very well. We had to accept the loss, I don't want to make excuses.
"Sometimes we are stretching the squad thin but we would have struggled with a full side out. We were comprehensively beaten."
Barnstaple were broken by three converted tries late in the first half, which saw the home side lead 31-3 at the break.
Linford Brock scored from a Steve Perry kick-through 10 minutes into the second half and Will Topps, who had earlier kicked a penalty, added the conversion to cut the deficit.
But Bracknell were soon back into their stride and completed the win with four more tries.
Their scores came from Ian Burch (two), Joe Price, Stuart Mackay, Daniel Antonelli, Dan Ap Dafydd, Stuart Silvester (two) and Oliver Taylor, with Liam Prescott kicking five conversions.
The last two teams to score more than 50 points against Barnstaple – London Irish Wild Geese in 2012-13 and Hartpury College in 2010-11 – have gone on to win the league.