View Full Version : Help me build my SDM-R
Im wanting to build a clone, or close replica, of my M16A4 SDM-R that I used in the Army. I have most everything figured out except the barrel and rail system.
White Oak has the barrel but I was wondering if anyone knew of another company that makes a similar barrel. Not that I have anything against WOA but multiple options are always good
http://www.whiteoakarmament.com/xcart/product.php?productid=17566
One thing I dont knw though is what rail system that my rifle had. It was a free float system. I have some not so good pictures but I cant tell what they are. Sorry for the dumbass in the pics.
http://i297.photobucket.com/albums/mm229/killerchase2000/Iraq%202003/dfADFD.jpg
http://i297.photobucket.com/albums/mm229/killerchase2000/Iraq%202003/sdasda.jpg
I think they were DD M4 rails with fluted Douglas barrels with rifle feed-ramps. I also think they had KAC 2 stage triggers. I'm 90% sure the FSB was secured via 4 set-screws also.
How concerned are you with it being an exact replica? I'd honestly look into a pinned FSB, and ditch the KAC trigger for a Geissele. It would have the look and feel of the original rifle with some functional improvements.
I think they were DD M4 rails with fluted Douglas barrels with rifle feed-ramps. I also think they had KAC 2 stage triggers. I'm 90% sure the FSB was secured via 4 set-screws also.
How concerned are you with it being an exact replica? I'd honestly look into a pinned FSB, and ditch the KAC trigger for a Geissele. It would have the look and feel of the original rifle with some functional improvements.
Those were exactly the changes I was looking to do. I found that BCM also makes the same kind of barrel for basically the same price.
JBecker 72
11-14-12, 16:21
Noob question regarding these SDM rifles. How much more accurate are they than your typical M16A4, and are they more finicky?
Noob question regarding these SDM rifles. How much more accurate are they than your typical M16A4, and are they more finicky?
Mine was a solid sub MOA rifle when shooting M262. But it wasnt that easy to shoot near its limits with the 4x ACOG. Your typical M16A4 is probably about a 2-4 MOA rifle when using standard ammo.
I never had a problem with my rifle. Being that the only real difference was a stainless barrel, free float rail and trigger I dont think you would see much if any loss in reliability. The match barrel does have a differnt chamber so that could possibly make a difference but I dont know.
JBecker 72
11-14-12, 17:11
Thanks for the info. Guess I didn't think they would be that much more accurate using issued ammo. I have found similar 2-4 moa results out of my 16" and 20" rifles using your typical ammo.
A build like this has me interested as I currently have a 20" A4 upper on one of my rifles, but find myself never using it because it doesn't shoot any better than my 16" middies do. I had looked at building a WOA 20" service rifle upper recently, but figure that would also not get used much. I had not given an upper like this much thought until just now.
JBecker 72
11-14-12, 19:01
Oh, and browsing elsewhere on this forum I just found this upper. Not sure how much it interests you, but it looks like a solid choice for a rifle in this category.
http://www.centurionarms.net/index.php?option=com_virtuemart&Itemid=176
Oh, and browsing elsewhere on this forum I just found this upper. Not sure how much it interests you, but it looks like a solid choice for a rifle in this category.
http://www.centurionarms.net/index.php?option=com_virtuemart&Itemid=176
That's more of a SPR upper. But would be a great precision rifle upper.
This is a write up for the 3 ID SDM-R's:
Weapon System Description.* The USAMU prototyped the Designated Marksman Rifle using the same technology for building National Match M16 competition rifles.* The USAMU Custom Firearms Shop removes the GI-issue chrome-lined barrel and replaces it with a heavy profile stainless steel match-grade barrel with 1-7 or 1-8 rifling twist.* The barrel has twelve flutes machined into the portion of the barrel covered by hand guards or the for-end rail system to reduce weight.* The front sight base is installed using Allen head screws vice drift pins to prevent barrel deformation and to provide windage correction when the iron sight on a standard M16A4 carrying handle is set to mechanical zero. The Modular Weapons System accessory rail is removed and a free-floating rail system is installed.* Free-floating provides consistent shot-to-shot accuracy, as the barrel is not affected by sling tension, firing position changes, or vibration changes from bipod pressure.* The free-float rails allow the Soldier to attach all standard accessories to the rifle, including optical, thermal, and Starlight sights; telescope; Aim point; the AN/PEQ-2 Target Illuminator/Pointer, and the AN/PAQ-4 Infrared pointer.* The standard M203 will NOT mount to the free-float rail (this requires a USSOCOM rail quick-attach M203).* The USAMU provides a modified Harris bipod with quick-detach hardware to fit on the accessory rail.* The standard blank adaptor fits the GI muzzle compensator.
Understood the rails where Knight as whee the triggers, depending on which document I look at. Seems like the barrels were Douglas.
This is a write up for the 3 ID SDM-R's:
Understood the rails where Knight as whee the triggers, depending on which document I look at. Seems like the barrels were Douglas.
Ehhh...I'm functionally certain, as in 99.99% sure, that the standard rail for these rifles, and the one pictured in the OP, is a Daniel Defense M4 Rail.
Rails were DD M4 12.0
I have built several of these using WOA and Superior Barrels (Douglas blanks profiled by CLE) and have had great results with every one of them. If I had one thing to change, however, it would be to go down to the 1/8 twist since it stabilizes the 77gr just fine.
The only issue I have with the BCM is that it needs to be bead blasted to get a good surface for the paint to stick.
Saleen
Ehhh...I'm functionally certain, as in 99.99% sure, that the standard rail for these rifles, and the one pictured in the OP, is a Daniel Defense M4 Rail.
And I stand corrected.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.