"Bullet" is so called because it moves fast and ends within a short period; as distinguished from most other platform programs which stay open for months and have typically 40-week terms or 1-year terms with 40 banking weeks.  Bullets with tear sheet privileges and a short period like 10 days are favored by the traders because it is very unlikely the investor would lose patience and move his money within ten days.  It is a short enough period for most clients to comply with the contract and leave the money intact until the payout.