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Posted: 1/24/2012 12:15:28 PM EDT
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Just received my DD 16" Mid-length upper and it has F-marked FSB with triangle handguard end cap. Being my first build, and not realizing it might come with the triangle end cap, I ordered a 2-piece quad-rail hand guard that looks in the photos like it will only work with a round end cap, but I'm not sure until it gets here.
If it doesn't, what are my options here? I'd like to be able to attach accessories to the handguard, whether it's a quad rail or an MOE. Are there any out there that work with the triangle end cap, or am I going to have to pull the FH & FSB/GB to get a different end cap on there? Thanks for any help. |
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I have 2 mid length uppers. One came with a round end cap and the other had a triangle end cap.
I added a MI 2-piece FF rails to both and they install and function great with either end cap. (of course FF HG's don't touch the end cap) I am not sure about non FF rails, but the original uppers came with the same type of round HG and fit either round or triangle just fine. It might help to know the brand of the rail you have ordered. |
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If your new handguards will not work with the triangle end cap, you can change out the end cap with relatively few "special" tools.
First, you will need to remove the flash hider. From what I've read here, two sections of a 2x4 work in place of a barrel clamp. I cannot yet confirm this, but I will be using this method tonight when I install a flash suppressor for the first time. Certain armorer's wrenches have a flash suppressor cutout, but a regular wrench should have no problem turning it. Next, you will need to remove the front sight base. You will need something to support the barrel/ fsb on something solid (I had to use a board with a hole drilled in to for the pins to fall into, laying flat on a concrete pad, and an oversized brass punch to get the taper pins to budge. Once they start to move, a smaller punch will drive them the rest of the way through. Your front sight base should now slide off of the barrel, and the gas tube and end cap will come with it. Swap end caps with the correct one. Slide the FSB back onto the barrel and into place. Use a punch to ensure that the taper pin holes are aligned with the barrel cuts. With the punch hanging out of one hole, push a taper pin into the other hole by hand. Make sure that the FSB isn't canted. Tap lightly to set the pin. Check again. Remove the punch and lightly set the next pin. Check again for FSB cant. Once you are satisfied that your FSB is on straight, to quote the Arfcommer who gave me this advice a few weeks ago, hit the pins like they owe you money. Last, re-install the flash suppressor. If yours came with a crush washer, you will need a new one. They are cheap. Buy one with your new end cap. Timing an A2 flash suppressor is pretty straightforward. Turn the flash hider until the crush washer deforms, then continue 90-270 degrees (stop when middle slot is at the top). The torque value listed here is 15-20 foot-pounds. Its kind of wordy, but easier than you might think. |
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Thanks for the instructions gingerbreadman. I hope to not have to do that.. but sounds straight forward.
I've got the UTG Pro 4/15 Mid Length 2-piece, non FF. I did some more research and believe it has nubs that will fit into either round or triangle end cap. If I decide to go FF in the future, I would think it'd be best to remove the end cap, but you're [SpringArm] saying that you have FF handguards and just left the caps in place? |
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Quoted:
Thanks for the instructions gingerbreadman. I hope to not have to do that.. but sounds straight forward. I've got the UTG Pro 4/15 Mid Length 2-piece, non FF. I did some more research and believe it has nubs that will fit into either round or triangle end cap. If I decide to go FF in the future, I would think it'd be best to remove the end cap, but you're [SpringArm] saying that you have FF handguards and just left the caps in place? The Midwest Industries 2pc free floats have just enough clearance to leave the cap in place. There are other 2 piece rails that require removal of the hand guard cap, such as Centurion Arms. |
| All midlengrh and rifle length should come with triangular handguard caps standard. All rails should work with those standard triangular caps. PSA are the only co i know of that puts round carbine caps on thier mid and rifle length. Some rails will work with the round caps on middys and rifles but not all. Triangular are the standard and you got the right cap for your middy. |
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