I have been a two time loser finding rails that fit the standard ACH and the Mid cut ACH, which should be the same.  I bought an Ops core and DLP set, bother did not fit, in best description, both were to small.  Can anyone direct me to a brand ans size that will fit size Large ACH standard and mit cut helmets?  Thanks!

I believe Tnvc has something

I have the Revision standalone rails on mine.  Large MSA TC2002 helmet for reference.  

There is a slight bit of overhang at the bottom where the missing "ear" part of the helmet is since its a mid cut.  It isn't bad at all and could probably be sanded down if it bothered someone.  

I'll try to remember to post a picture tomorrow.

Here's a couple of pics.  Revision standalone rail on. Large MSA TC2002.




This is the amount of overhang I have at the rear of the "ear" cutout.  Not bad at all really.

What type of cover is that?

Revision Viper Premium mid cut cover.  

Apparently Revision only deals with eye protection now. The rest of their stuff like helmets etc are through a company called Galvion.  The Premium mid cut cover isn't listed on the Galvion website but it wasn't listed on Revisions either.  They do list a "Basic" mid cut cover though.

A year or so ago I called Revision and asked if a Premium cover existed for mid cut and they put an order in for me over the phone/email.  Not sure if that's still an option with the name change but worth a shot if it's what you're looking for.

Thanks for the info.  Galvion has a basic one listed.  I think that is all I will need.  Do you know the differnce between the two covers?

No problem.  I think the basic is pretty much just a plain camo cover while the premium has velcro patches all over and elastic foliage loops.

So I finally found the rails, but the screws are too short.   Any idea where to get longer screws to go through the tails and onto the helmet straps?

Some rails I purchased came with longer bolts, some didn't. I used some different bolts I already had to mount a couple sets. I need to order some different bolts also.
Here are some.
https://ownthenight.com/helmets/product/12834-ops-core-replacement-ballistic-hardware-kit-22mm/category_pathway-31

I was at Rural king today and they have some m6x22 bolts. You asking about bolts reminded me to look for some when I was there. They seem to be good quality bolts and look just like typical rail bolts except they're phillips head vs. flat head. I'm fine with them being phillips head since it saved me from ordering online. I also saved about $50 compared to ordering 3 sets of Opscore bolts. I spent $12 for 12 bolts because I needed to change out the bolts on 3 helmets. I already had the chin strap nuts like most people, I just needed the bolts. If you have a Rural king in your area and can live with phillips head, it's another option.