Using an adapter forces you to stack tolerances, which is never ideal. Each part has its own dimensions and will never match up precisely like a single piece. This increases your chance of a baffle strike, which will likely ruin your suppressor. But, if you want to suppress your AK, you may not have a choice.
Another issue with an adapter is that Kalashnikov barrels don’t have a shoulder on which to index. The Russians used the front sight block. Using an adapter makes that a bad idea, especially since AK sights are notoriously “individual.” Russian muzzle devices are often wider than necessary to account for that.
But suppressors are much more precise. Even the slightest bad angle can lead to a baffle strike. Any adapter you use must be indexed to the muzzle, not the front sight to mitigate that risk.
Barrel Concentricity
As noted, Kalashnikov rifles are not the same across the board. Even some bores don’t match the barrel exactly, meaning you must test for that before using your suppressed AK for real. This is easily accomplished by testing it with a rod.
