Rail standards

[Bruce in WV]

A recent thread (https://www.m4carbine.net/showthread.php?t=82404) contained some strongly negative remarks about the YHM rail without specifying why it is so bad. I can find no standards listed in the stickies on the technical forum to help me understand why the writers felt so strongly about the brand. I am concerned because my gunsmith put a rail by the same manufacturer when building my Armalite based upper.
What standards should a person apply when considering the purchase of a rail? Are they subjective or objective, related to materials and quality of machining, or something else? Any help would be appreciated.

[lethal dose]

Honestly, it comes down to what you're going to be doing with the said weapon. I wouldn't say yhm is junk, but it certainly doesn't live up to the standards larue, troy, dd, and other companies have set. Their designs are outdated and grossly overweight... if you're ok with that, shoot on. MI makes a very solid piece of kit... same story. As long as it's in spec, you should be ok. Now, their other parts like BCGs and whatnot, I'd steer clear... although, I'd personally steer clear of their rails, too.

[rob_s]

When evaluating FF rail systems it is largely subjective except for two things: adherence to the Picatiny Rail dimensional drawings and the stgregth of the mounting system at the barrel nut. Historically YHM has had trouble in both categories.

Subjective categories are going to include cost, ID, height, width, weight, available lengths, inclusion of QD swivels, modularity, "feel" in hand, etc. IME YHM fails in all of these categories save cost and maybe ID for some nested suppressor applications.

YMMV

[Bruce in WV]

Thank you.

[rob_s]

For the subjective (https://spreadsheets.google.com/pub?key=pwswheghNQsFnUZMkZNF2DQ&output=html)

[markm]

Honestly, it comes down to what you're going to be doing with the said weapon. I wouldn't say yhm is junk, but it certainly doesn't live up to the standards larue, troy, dd, and other companies have set. Their designs are outdated and grossly overweight... if you're ok with that, shoot on. MI makes a very solid piece of kit... same story. As long as it's in spec, you should be ok.

Exactly. If you list your needs/wants and priorities, we could offer suggestions.

Is weight a priority? Do you want Free Floated? etc....

[Bruce in WV]

to help with the analyses to optimize my set-up. The table from Rob_S is a great tool to supplement the other stickies. I'll be able to use it to re-think my requirements, needs and wants for BUIS, optics, light, vertical grip, sling, etc in the context of rail quality, weight and size.

[Stickman]

A recent thread (https://www.m4carbine.net/showthread.php?t=82404) contained some strongly negative remarks about the YHM rail without specifying why it is so bad. I can find no standards listed in the stickies on the technical forum to help me understand why the writers felt so strongly about the brand. I am concerned because my gunsmith put a rail by the same manufacturer when building my Armalite based upper.
What standards should a person apply when considering the purchase of a rail? Are they subjective or objective, related to materials and quality of machining, or something else? Any help would be appreciated.

One of the largest problems I've seen with YHM rails is them coming loose, even when torqued down hard. Specs for the rails can be good in one batch, and later on off on another. QC seems to not be the strong point, with more of an emphasis on price point.

[Iraqgunz]

This opinion is based solely on my experience with our particular Bushmaster carbines in Iraq that were equipped with the YHM rail with a flip up type sight mounted on the cut down FSB. I had a total of 500 of them in the armory.

From the factory they were installed incorrectly. There was no anti-seize used and in fact I think some type of Loc-tite or Rocksett was applied to the barrel nut. This made it extremely difficult to remove them when needed. Some would come loose with a little heat and muscle, others have to be cut off with a Dremel.

The jam nut which tightens against the rail was crap. You need a special wrench from YHM for the install, however the surface area where the wrench grabs it, is not very large and because of the way they were installed more often than not I couldn't break them loose without damaging something.

The rail we had did not have any type of anti-rotation screws installed and there were frequent issues with the rails moving. Part of this was due to the sling mount which mounted to the rail (see also lack of anti-rotation screws).

The barrel nut was made of aluminum and again due to the design and the previous installation very difficult to remove. I broke at least 3 wrenches during the time I was working on them and unknown number of barrel nuts as well.

We also had issues with the rails mating up to the upper receivers. They were very difficult to line up properly

In all they are not made for real use. They are great for airsoft, but if you are using them under hard conditions they are going to be problematic. I would have preferred no railsand simple handguards over them.