I finally decided to take off my M4 style plastic handguards (which I love so dearly), and put on my Knights Armament rails. A two piece deal that should only require me to open the delta ring, pull off the plastic handguards, and replace with my rail system.

Only Problem is...

the delta ring side of the upper forearm won't close together with the bottom rail which appears to fit perfectly inside the delta ring. The inside of the top rails are a small metal channel which appears to mount and fit around the gas tube (with a screw to adjust the height on the T14 rail outside). It won't seem to close together to fit inside the delta ring. It won't close by about 1/8" and I don't want to break or bend the gas tube trying to manhandle it closed.

What the Hell?



ETA:  I obviously removed the top screw to allow the gas tube to fit all the way at the top of the forearm.

any help?  please

Quoted: I finally decided to take off my M4 style plastic handguards (which I love so dearly), and put on my Knights Armament rails. A two piece deal that should only require me to open the delta ring, pull off the plastic handguards, and replace with my rail system. Only Problem is... the delta ring side of the upper forearm won't close together with the bottom rail which appears to fit perfectly inside the delta ring. The inside of the top rails are a small metal channel which appears to mount and fit around the gas tube (with a screw to adjust the height on the T14 rail outside). It won't seem to close together to fit inside the delta ring. It won't close by about 1/8" and I don't want to break or bend the gas tube trying to manhandle it closed. What the Hell?

Is it safe for me to assume that you have a KAC RAS? If so...There is a gray swing lock that is that channel you refer to, a hook if you will, on the inner portion of the top rail that slides under the barrel nut. To allow the little hook to swing down you need to remove the little allen head screw from the top of the rail. Once you do this let it hook swing all the way down, install the front of the rail to the handguard cap & then ease the rear of rail downward making sure the hook slides under the barrel nut & then snap into the delta ring. Replace the screw & tighten it down & you're done. Provided that you do have a hbar on the extreme side of that profile diameter you should not have much trouble getting the rail locked in.

There is a more elegant tutoral for installing a RAS floating around here somewhere but if you can't find or have more trouble send us another line.

Quoted: Quoted: I finally decided to take off my M4 style plastic handguards (which I love so dearly), and put on my Knights Armament rails. A two piece deal that should only require me to open the delta ring, pull off the plastic handguards, and replace with my rail system. Only Problem is... the delta ring side of the upper forearm won't close together with the bottom rail which appears to fit perfectly inside the delta ring. The inside of the top rails are a small metal channel which appears to mount and fit around the gas tube (with a screw to adjust the height on the T14 rail outside). It won't seem to close together to fit inside the delta ring. It won't close by about 1/8" and I don't want to break or bend the gas tube trying to manhandle it closed. What the Hell? Is it safe for me to assume that you have a KAC RAS? If so...There is a gray swing lock that is that channel you refer to, a hook if you will, on the inner portion of the top rail that slides under the barrel nut. To allow the little hook to swing down you need to remove the little allen head screw from the top of the rail. Once you do this let it hook swing all the way down, install the front of the rail to the handguard cap & then ease the rear of rail downward making sure the hook slides under the barrel nut & then snap into the delta ring. Replace the screw & tighten it down & you're done. Provided that you do have a hbar on the extreme side of that profile diameter you should not have much trouble getting the rail locked in. There is a more elegant tutoral for installing a RAS floating around here somewhere but if you can't find or have more trouble send us another line.

ahh ha. I think that's it, thanks. Unfortunately my second pair of hands already went to sleep, so I'll have someone help me in the morning. That delta ring sure takes a toll on your fingers.

you know, it's a lot easier said than done trying to get that little swing hook to stay down and hook underneath while holding the upper vertically and pressing down on the delta ring. Thanks again for your help, I think I'll manage to get it in their eventually.

Quoted: you know, it's a lot easier said than done trying to get that little swing hook to stay down and hook underneath while holding the upper vertically and pressing down on the delta ring. Thanks again for your help, I think I'll manage to get it in their eventually.

You are correct sir. If you have a forearm removal/installation tool then it's a bit easier. This tool allows you to hold the upper at less than a vertical angle. It's easier for the swing arm to remain at its lowest point when holding the upper only at the angle acute enough to allow this item to slide under the barrel nut & then release the delta ring if that makes any sense? Holding the upper vertically tends to make the swing arm want to swing back under the rail rather than hang low.