I bought a Seekins SAR because my AAC silencer specs said 1.5" OD and the SAR specs said 1.5" ID. The SAR also said 12" everywhere I looked, while other brands said 12.5". The can starts at 11.75", so I expected 1/4" overlap and thought some light sanding may be all that was needed.

I finally got my can this weekend after the long wait and found the QD button sticks out another 16th", which means I need at least 1&5/8" ID on the rail if it's going to overlap the can at all. I also noticed the SAR rails are actually 12.5" despite all their advertising saying 12.0". The rail would need to be no longer than 11.75" if there's no overlapping the can.

I'm looking for 2 options:
A) What is the lightest reputable rail on the market which has full length top and bottom rails and is </= 11.75" and at least 1.365" ID?
B) What is the lightest reputable line of rails on the market which have full length top and bottom rails and are >11.75" and at least 1.625" ID?

PA

That's one option. Bump for others.

Anyone know of a "monolithic" upper with 11.5" rail section? I noticed my Seekins SAR Gen II rail sits crooked from the barrel by a visible amount.

PSA 12" Rail is actually 12.5"

I called PSA and found out the same thing. It may work, but is a runner up to something an inch shorter.

I was just searching for a new upper & forearm, and came across the Aero Precision Enhanced rails.  They have a 1.8" inside diameter, which should work for your configuration.  FYI - their "enhanced" rails require a proprietary barrel nut to mount to a standard upper receiver, but I'm looking at getting their "Enhanced" upper receiver that has the special nut integrated.  

http://aeroprecisionusa.com/handguards.html

Hopefully that helps!  I saw it on sale at Schuyler:  http://www.schuylerarmsco.com/catalog.php?category=104562

I found Fortis makes a REV in 11.5" with a cutout for the gas block. I have a micromoa govnah, which I planned to adjust by poking through the holes in whatever rail I got, but maybe a cutout is a good option. That 11.5" OAL will also give me 1/4" clearance for the QD button on my silencer. Seems like a good option, but I'm weary about the mounting system; seems it could wobble, or loosen the barrel nut if banged around. Any experience? Know anywhere to get a deal on one to try (this is the best I can find and seems a bit high: $210)?

With the 1/4" overlap that you originally intended, how would you depress the QD tab in order to remove the suppressor?

Can you remove material on the rail in order to make it work? (possibly rendering the QD sockets on the rail inoperable)?

With any overlap, I would have needed a rail with either large enough holes in the sides(more necessary as the rail gets longer) or a large enough gap between the inside and the can to fit something to push with (easy with 1/4", but hard with much more).

You check out the Samson Evo?  ALG EMR?

ALG definitely won't work for me in this application, although the lower does have her trigger. The Samson is a good backup option to the Fortis.

I would have liked the LMT, but $1,000 for an upper?! AYFK? Does it aim for you? They have a terrible marketing plan.

JL Billet makes an 11" rail.  Also has sale for July 4th right now...

eta: forgot that you want a lower rail as well, which the JL Billet does not have, but include rail sections to be mounted on if needed...

Samson offers both a regular and key mod 12.37 in rail that mounts with a milspec barrel nut. Their videos say the ID is 1.56

[youtube]https://youtu.be/M4VKW2VwS_Q?t=2s[/youtube]

So your can should be good as long as the OD is less than 1.56

see the video at the 10 sec mark if you don't want to watch the who thing. I have them on all my ARs

Also on sale at midway time now