Simple fix I came up with for my AK replica with 550mm inner barrel hidden by a suppressor.
The issue comes from the fact that the outer barrel is a bit wider and that causes the inner
barrel to wobble. Furthermore, the suppressor end is much wider than the inner barrel which makes it ugly.
I fixed that by designing a stud with a hole to fit the suppressor to inner barrel gap
and then a cone shaped object to stabilize the barrel in one place.
Now the shots are quite consistent!
Reach out to me in case you need the STL files to print your own objects.