Not that I'm aware of . I used talleys they worked fine on mine but I just tossed a 4.5-14 leupy I had on it and called it good its so light I planned on just using it for deer and dark timber 300 and in stuff
APA 30mm lows. I've had .82" Seekins lows and the APA's were better on the height, though it isn't a massive change. Using the previous version of APA low's on the NULA, the current is a touch wider but the same height....really well designed ring if you're looking for a lower mount on a rail:
The APA Gen 2 30mm Tru-Loc Scope Rings are among the strongest in the world due to their unique design, premium materials, and unmatched build quality. They possess the ability to return to an infinite zero because of the engineering geometries utilized. Available in three different heights...
As SDHNTR mentioned, the Farrell's are going to be a bit lighter. I posted about some of the differences between the Farrell's and APA's a while back but IMO, the APA's are much better rings. The Farrell's are light and trim but because of the lightening cuts and thin width of the rings, there's a lot less tube to ring contact with them compared to APA's. I prefer the lug and latch system of the APA rings. Easiest way to explain the difference in contact and gripping area between the two: