A pretensioner (20) for use with a seat belt system, the pretensioner comprising: a straight first tube (22) having a cylindrical wall (22a), a first end (24) and a second end (26), at least one of the first end (24) or the second end (26) having an opening (32); the first tube includes a first opening (38) in the wall (22a) to receive a second tube (50), the second tube (50) having a first end portion (52), a second end portion (56) and a medial portion (54), the medial portion configured to have a circular curvature of radius R1; the second end portion is situated so that its center is collinear with a central axis (64) extending through the center of the first tube (22) and wherein an axis extending through the center of the first end portion is arranged at an acute angle relative to the central axis (64); a pyrotechnic element (40) is provided at one end of the first tube to provide products of combustion to drive a piston (100) down the first tube, the motion of the piston moving a cable (80) in a direction to move a seat belt buckle to reduce belt slack about an occupant to be protected.