A mix chamber configured to be disposed in a bore of a plural component spray gun and configured for receiving a first component fluid from a first fluid channel in the plural component spray gun and a second component fluid from a second fluid channel in the plural component spray gun, a first side seal is disposed in the first fluid channel to seal against the mix chamber and a second side seal is disposed in the second fluid channel to seal against the mix chamber, the mix chamber comprising: a chamber body extending between a first end and a second end and elongate along a body axis, the chamber body including a first flat lateral side and a second flat lateral side; a first inlet bore extending into the first flat lateral side and to a mix bore extending to a spray orifice, the first inlet bore configured to receive the first component fluid from the first fluid channel; a second inlet bore extending into the second flat lateral side and to the mix bore, the second inlet bore configured to receive the second component fluid from the second fluid channel; and a ramp feature (116a, 116b) disposed proximate the first end, the ramp feature configured to contact and push the first and second side seals (88a, 88b), respectively, away from the body axis as the mix chamber shifts in a first direction through the bore of the plural component spray gun to increase a gap between the first side seal and the second side seal such that the first side seal engages the first flat lateral side and the second side seal engages the second flat lateral side; characterized in that the ramp feature comprises: a first ramp formed between the first flat lateral side and the first end, the first ramp providing a sloped transition between the first end and the first flat lateral side; and a second ramp formed between the second flat lateral side and the first end, the second ramp providing a sloped transition between the first end and the second flat lateral side. a chamber body extending between a first end and a second end and elongate along a body axis, the chamber body including a first flat lateral side and a second flat lateral side; a first inlet bore extending into the first flat lateral side and to a mix bore extending to a spray orifice, the first inlet bore configured to receive the first component fluid from the first fluid channel; a second inlet bore extending into the second flat lateral side and to the mix bore, the second inlet bore configured to receive the second component fluid from the second fluid channel; and a ramp feature (116a, 116b) disposed proximate the first end, the ramp feature configured to contact and push the first and second side seals (88a, 88b), respectively, away from the body axis as the mix chamber shifts in a first direction through the bore of the plural component spray gun to increase a gap between the first side seal and the second side seal such that the first side seal engages the first flat lateral side and the second side seal engages the second flat lateral side; characterized in that the ramp feature comprises: a first ramp formed between the first flat lateral side and the first end, the first ramp providing a sloped transition between the first end and the first flat lateral side; and a second ramp formed between the second flat lateral side and the first end, the second ramp providing a sloped transition between the first end and the second flat lateral side. a first ramp formed between the first flat lateral side and the first end, the first ramp providing a sloped transition between the first end and the first flat lateral side; and a second ramp formed between the second flat lateral side and the first end, the second ramp providing a sloped transition between the first end and the second flat lateral side.