Here is an updated version of the particle system that has longer lasting particles so the smoke effect is stronger. Note that having a lot of particles will impact your frame rate.
Code:
ParticleSystem A10MuzzleSmoke
Priority = WEAPON_TRAIL
IsOneShot = No
Shader = ALPHA
Type = PARTICLE
ParticleName = exsmolderingflamesmoke.tga ;exsmokepuff.tga exsmokepuf04.tga
AngleZ = -1.00 1.00
AngularRateZ = -0.01 0.01
AngularDamping = 1.00 1.00
VelocityDamping = 0.70 0.80
Gravity = 0.00
Lifetime = 60.00 90.00
SystemLifetime = 1
Size = 2.00 4.00
StartSizeRate = 0.00 0.00
SizeRate = 1.20 1.50
SizeRateDamping = 0.70 0.80
Alpha1 = 0.75 0.75 0
Alpha2 = 0.60 0.60 10
Alpha3 = 0.00 0.00 90
Alpha4 = 0.00 0.00 0
Alpha5 = 0.00 0.00 0
Alpha6 = 0.00 0.00 0
Alpha7 = 0.00 0.00 0
Alpha8 = 0.00 0.00 0
Color1 = R:125 G:125 B:100 0
Color2 = R:162 G:162 B:162 10
Color3 = R:192 G:192 B:192 90
Color4 = R:0 G:0 B:0 0
Color5 = R:0 G:0 B:0 0
Color6 = R:0 G:0 B:0 0
Color7 = R:0 G:0 B:0 0
Color8 = R:0 G:0 B:0 0
ColorScale = 0.00 1.00
BurstDelay = 2.00 2.00
BurstCount = 1.00 3.00
InitialDelay = 0.00 0.00
DriftVelocity = X:0.00 Y:0.00 Z:0.00
VelocityType = ORTHO
VelOrthoX = 12.00 13.00
VelOrthoY = -0.20 0.20
VelOrthoZ = -0.20 0.20
VolumeType = POINT
IsHollow = No
IsGroundAligned = No
IsEmitAboveGroundOnly = No
IsParticleUpTowardsEmitter = No
WindMotion = Unused
WindAngleChangeMin = 0.149924
WindAngleChangeMax = 0.449946
WindPingPongStartAngleMin = 0.000000
WindPingPongStartAngleMax = 0.785398
WindPingPongEndAngleMin = 5.497787
WindPingPongEndAngleMax = 6.283185
End