I assume these rails are left over from the IAR trials. Is anyone else using these to do their own builds? Here is my version of an IAR:
https://youtu.be/ArFAGIz0YD0

Viewer number 25 here.

Great video and info.

That was very interesting. Thanks for making the video.

I hadn't seen those rails before. They're pretty cool looking.

Any pictures of this rail installed with a carbine length FSB?

CDNN had the Colt complete uppers with the same rail for sale not too long ago. I believe they were close to around $2000 (I may be mis-remembering the price).

Very cool.

I went with a POF heat sink barrel nut handguard system in a similar intended build not too long ago.

I would be interested to see how they compare as far as heat disapation.

Sweet build.

I have had several guys ask where these are. They are $300 on the big auction site. Search for "Knights Armament Colt IAR Handguard" under gun parts, AR15.

Nice video Mike.  I'm looking forward to seeing how she runs.

I purchased one, should be here in a day or two. Not sure what I am going to do with it yet. I have a spare Colt stripped lower in the safe; but, I keep thinking I should go full retard on a SR15.

I am waiting for the loggers to finish thinning out the trees on our property so it will be after Thanksgiving before I test fire my version of the IAR. I would like some feedback from the hive on testing. The sustained rate of fore of the M16 is 12-15 RPM and the M27 IAR is 36 RPM. Since this build is about managing heat for a higher sustained rate of fire I thought the most appropriate evaluation would be doing a steady sustained rate of fire of 36 RPM for 10 minutes or so. I can monitor surface temp to make sure we hit the maximum and the temp plateaus within 10 minutes of that rate. The malfunction I am looking for is a cookoff. I'll use LC M855 and keep a round in the chamber at the end of the test until the rifle begins to cool off. I can check muzzle velocity. My build has an 18" barrel rather than 16.5". I will load 36 rounds in 10 40 round Magpuls and empty over 1 minute each. Any other thoughts about what to look at with this build?

I’m jealous. I have some old growth pines on 76 acres that a state biologist told me to have logged. Trying to get a logger during hunting season is next to impossible. Plus, they all have jobs lined up; but, on hold while they are out hunting. Maybe in 5 months or so they might get to me.

USPS says my rail will arrive today. Looking forward to viewing your test video.

Honestly a bone stock M4 wouldn't have a cook off with 10 40rd mags spaced over 10 minutes.

Reminds me of VLTOR's CASV handguard/rail, minus the piggyback.

Mine came in today. They shipped it by slapping a label on the KAC box, no packing materials inside. One end of the box was crushed in shipment. Luckily, the rail was undamaged. What a joke.





FYI- I measured the two holes in the front of the lower rail, they are 1.40” center to center. The pins on my Colt 6943’s GB/FSB are 1.40” center to center.  I’m no gun plumber, so my measurements might be slightly corse. The only picture I could find of the KAC IAR Show a Rifle with a rail almost twice this length; but, looking very similar. It had a gas block with a picatiny rail on top. This one is for a Carbine gas system; or, maybe it was a piston system.

I think you might be surprised if you took a M4 barreled carbine and shot one round every 1.5 seconds for 10 minutes without stopping except for rapid mag changes and then chambered a round immediately at the end of the 400 round run and waited, keeping the muzzle in a safe direction.

mBell, any updates?

Out of town. Will be back next week. Hopefully loggers will be done with thinning our trees and I'll get out and do some test firing. Still undecided about how I want to function test it to see how it handles heat.