Does not fit as stated - BlackHawk Mossberg 590 / 835 Shotgun Swivel Set 70SW29BK

I bought this set to attach a sling to my 18.5" Mossberg 590A1 and the mag cap got stuck as soon as I tried screwing it on. I verified there is no damaged to the threading on the gun and cap and even added a little gun oil for lubrication - same result, had to use a wrench to get it off again. The original goes on without effort. I sent it back (RMAed) to Opticsplanet, detailing my gun model and the issue with the threading. Waiting almost 2 weeks to get a replacement delivered and it is the same issue. The treading on this cap is wider than that of my 590A1 and thus it get stuck very easily as soon as it is screwed on. Worst experience on this site ever. You would think they would test before completing an RMA request.
Cons: does not fit my mossberg 590A1

This review was written in the old system and had content requirements that are different than reviews written today.