YHM SLR rail
YHM has just listed the new SLR rail on their website, while it is out of stock at the time of writing, it should be available for purchase soon enough. The new forend comes with a proprietary mounting system that, like all free floating rails used on a regular upper, mounts to the barrel nut. However the barrel nut is not the regular nut, it is a proprietary nut that is a significant improvement over the standard. As the regular barrel nut was never designed to receive a free floating rail attachment, I have always had some concern with rails that use it in that way and the potential for a rifle length rail to put enough torque on the standard barrel nut to adjust the rails precise alignment. Which, at a minimum, destroys your iron sight zero and any PEQ or day laser attachments you might have.
It is is a solid rail and system. Certainly stronger than most rails. To name a couple of brands for comparison would rank it equal to Samson and above Troy. Though without destructive testing that can only be considered my opinion, I have seen a lot of rail systems and what weaker ones can take. Certainly it can take more of a beating than any rifle should be put through. The mounting system takes 5 screws and allows you to perfectly line up the top forend rail with the upper's top rail without having to adjust the barrel nut at all. Once the screws are tight, it binds very well - the alloy of the barrel nut is harder than the aluminum of the rail collar so the aluminum conforms slightly to the cross pattern on the nut.
There are 2 configurations in the SLR available: A quad rail as pictured on this review and a cleaner forend that allows bolt on rails. It is worth a look as it is one of the more unique rails of that type.
YHM says their rail for sure fits over the Adams and CMMG gas pistons and any other brand that is not significantly bigger than those two.
With an MSRP of $230 for a rifle length quad rail, the SLR is well targeted for anyone wanting a stronger than standard rail system. To compare it to the Troy MRF, it is $1 more and a lot stronger. I realize Troy says they have the strongest "user installed" mounting system in the world. However the key is in the "user installed" part. Most manufacturers recommend only having a trained armorer install a barrel nut. Personally, having seen many barrel nuts come incorrectly torqued from many a factory, I don't trust any stranger, certified or not, more than myself to change out a rifle part. As a side note, the YHM barrel nut came perfectly torqued right out of the shop.
NOTE on pictures: If you right click, you can save or open them in a new tab, they will then be bigger and easier to see detail.
The YHM barrel nut is a significant improvement on the standard barrel nut
Set the forend in place, line it with the rail on the upper then bolt the lower collar on
I will test the rail more over time and update this page as I do, I will also have it tested by some people I trust to push it hard in the meantime. So far I have only had the ability to put about 10 magazines through it from a few positions.