Didn't fit on my 16" Saiga .308.
Hopefully this is useful information.
The barrel was too wide at the base. The heat shield has two sets flanges, forward and rear) that come up over the left and right side of the barrel, behind the m-lok holes. The rear flanges are too tight to fit around the barrel and sight block barrel band that is there. The forward flanges are OK because the barrel is more narrow there. So, if I took a mallet to the heat shield and bent the rear flanges to fit around the base of the barrel, the rear flanges would then no longer be aligned with the front flanges and I don't know if the plastic would be able to bend enough to accomodate both sets of flanges.
That's a shame -- plum would have looked good on that gun.
I wonder if it'll fit on my VEPR...