Frame rate = 30 or less ( it is very unnecessary to record video in 60 fps for pattern recording as many unnecessary movements )
i use Nvidia highlights with 30 fps
record video ( 30 fps or less ) of gun without attachments and with attachments in one go, that is at same location and same distance.
otherwise when you adjust weapon specific recoil of the gun there will be mismatch of recoil control while you are equipping attachments for the gun and while you are not equipping attachments for the gun.
this is very crucial, while recording pattern
after trimming to work area, do a warp stabilization ( i usually set warp stabilization to 1% ) , then export it.
after that create new project from exported video
then track motion
this will give better and smoother pattern