With the recent introduction of the Squad Marksman rifle ( in 5,56) being seen in many photo's on the web,I have  questions for those of you who were there or used this type of rifle in the Sand Box.
There seems to be several types being used. What did you use or see being used? Did it have a quad rail that did not float,or was it free floating? Did it have a fluted barrel of just heavy contour.
Was the trigger issue or was it a drop in packet type?  Did it have a unique muzzle brake or flash hider? A bi-pod? Was there anything special about the stock?
And lastly,what scope did you see or use? Power? It seems that each service uses their own modifications or is there a standard that has requirements that must be met?
Rather than guess I would really like to hear from the fellows who used them or saw them being used.
Thank you for your time and thank you for your service.

Are you talking specifically about the US Army SDM or the USMC SAM-R?  The are 2 different models that vary slightly but both have 20" barrels.

I'm looking for first hand use of any services use of these rifles and the configuration of that rifle. My post says that there are differences between the services,I'm just interested in the 5.56mm caliber rifles that members have knowledge of.

Pic of 3ID soldiers with SDM Wikipedia
They are made by the AMU which is in Ft Benning and 3ID is there as well so these would pretty much be the standard.
SS barrels painted black and fluting his hidden under forearm the weapon is made to pass as a more or less standard rifle from a distance.
1/7 twist barrels but a 1/8 would probably suffice for all but the lightest bullets and the heaviest tracers you could use.

You make it sound as though the appearance is intentional rather than simply resulting from a lack of exotic parts.
So is it standard in appearance due to AMU using parts from service rifle competition that they would likely have experience with and a supply chain for or have our current enemies shown a tendency to target atypical appearing soldiers?

google is our friend

Officer/NCO in charge
Guy with a radio
Belt fed machine gun
scoped rifle
is pretty much how the order went in targeting in most recent wars.  
This was the reasoning also given in a 2008 article in Military Newspaper on Ft Benning in an article on the DMR.
Ability to operate without direct supervision by US is not necessarily a factor in how the enemy will prioritize targets.

As to experience with our enemies targeting atypical appearing soldiers why would we wait for them to target the Designated Marksmen before making them blend in as much as possible?

I would add corpsman/medic to that list.  My experience with the SAM-R was Douglas barrel, free-floated, with 3-9 scope.

With the help of members I was able to buy and piece together a representation of a Squad Marksman rifle. The scope I ordered will not be here until next year so I placed an older scope on it to sight it in.
The barrel is Heavy contour straight fluted 20". 1:8 Twist
Upper receiver is a Cerro Forge
Lower receiver in a DPMS
Receiver guts are Spikes
Butt stock and buffer goodies are GI
Folding Rear sight is Troy
Folding front sight is PPP
Free float fore end is a Midwest T-series
Gas block is UTG w/ GI gas tube
Flash hider is A2 GI
Scope mount is not maker marked but is for 5.56 trajectory
Harris bi-pod
Yankee hill bi-pod adapter
AO Precision BCG
A red dot scope and 3x magnifier is on its way as well.

Thank you to all who replied with info on these rifles and how they were set up.

What's your all up weight on that bad boy?

Cool looking rifle. Harris bipod legs should be facing forward.

In recent years, the Marines have also pressed the Mk12 Mod 1 into service as a DMR. If you peruse the Mk12 thread you will see Marines deploying it in the same manner as the SAM-R/SDM, sometimes with/without suppressor. You can also engage a few guys in the Mk12 thread that used them in exactly that role overseas, most I've read gave favorable feedback. Remember that any of these rifles are heavier than their standard counterparts, which also weighs in guys opinions about carrying one around.

Oh, and the SDM/SAM-R/MK 12/ M14 DMR aren't really a new thing just popping up online. The concept has been around a long while, older pics show guys with personal scopes on carry handle mounts before the flat top uppers came around with the M16A4 and M4. Even the old M1903A4 and the M1C/D's were more of a DM rifle than what we consider a "sniper rifle".

Thanks for the bi-pod leg tip,I'll reverse it. Should it stay up front or be back towards the mag well? I've seen it both ways?
The rifle has to be close to a M-14.I'll weigh it.

Mine was built at the unit level. Rack grade A4 with a KAC free float RAS and a USO SN-4.  I argued for a 3-9x leupold but the XO fancied himself a gun guy and was in love with the idea of a 1-4x. It worked out ok. This was a long long time ago when they were still issuing M14s and there was no official program from the war fighting lab on this. There was some administrative reason why we couldn't get match triggers but I don't remember what it was, only that it was ridiculous.

Interesting they'd let your armory do the FF RAS but not do a trigger. You think it had to do with buying NFA parts, or typical "that's too cool/smart so we can't" USMC bull? I'm guessing the KAC trigger would have been on the market at the time and was used elsewhere, weird they couldn't at least get some of those.

In 2011 Helmand AFG we used Mk12 MOD 1s, but a majority of our DMs used M39s for what that's worth, I know you said mostly 5.56 was of interest, but hey knowledge is power. I was Marine Artillery by the way, not an infantryman.

Definitely would not peg this as a representation or a clone in any way.

The rifle weighs 12 pound on the dot with a loaded magazine.
I have gathered my info from members here and elsewhere who have had this type of rifle over the years. I have used their info and sent photo's of their rifles. The rifle is not any one Mark,Mod,Make,Type,bla,bla. It is a concept with parts that are available from the past and now that follows the concept.
In the future a drop in trigger pack and the appropriate optics will be added.
I test fired the rifle tonight and it functions as it should. A range report will be done this weekend.
Thanks again to those who have contributed info and parts for this build.

I placed a man silhouette at 300 meters and tried out the rifle. I brought 55,62 and 75 grain loaded ammo. The wind was calm and the sky overcast. The scope is a real POS but did work OK. The 1:8 barrel did a very good job with the 62 and 75 grain bullets. The 55's were overstabolized  and the group open up by 6". All loads functioned as they should.Once I get the drop-in trigger pack I should be able to close up the group a little more.
Here is the 300 meter target,20 rounds fired:

"Squad Designated Marksman," for most units refers to a position in the TO&E, not to a specific rifle configuration.  

While there are some examples of special, purpose built rifles out there, like the USAMU's 20" SDM-Rs for 3rd ID, and 18" Middies for 82nd Airborne, and the SAM-Rs and MK 12 MOD 1s in the Marine Corps, these were all built/issued in relatively small numbers compared to the number of "rifle squads" out there in the force, both Army and Marine Corps.  

The "average" SDM or SAM rifle is nothing more than a stock M4 or M16A4 with an ACOG, whichever was issued to that particular unit, and then "customized" based on the specific user's preferences/what they decided to buy for their position.  

A lot of units purchased Harris BRM and BRM-S bipods at a unit level, so many ended up with those bipods, either that, or pulled off of other systems that were seeing less use/swapped around, etc.  Once they started issuing Grippods to everybody, though, even that fell by the wayside.

Some units will do more or less at a unit level and/or allow a certain amount more leeway to modify the weapon, i.e. COTS FF rail systems, etc. but there is not any particular set "standard" or "pattern" for this, and as GWOT has gone on, the trend has been to more standardization in basic configurations and away from allowing too many modifications, either at the individual or unit levels.  

In all actuality, the basis of the SDM has more to do with how a ground leader chooses to utilize a particular soldier - hopefully they're considered a particularly good, with luck some of them might be "school trained" for the SMD role, but from what I have seen, in a lot of units, the SDM role is little more than a "title" for an MTOE position, and unit SOPs about what to do with these particular troops vary widely.  The amount of emphasis they receive from the leadership also determines the level of support they get in having "specialized" weapons.  

As has also been mentioned, there's also been the use of other systems in a dedicated marksman role, at various echelons, including, but not limited to M110s, M14/M39s, M27 IAR in a DM role, etc.  

Basically, your "squad marksman" rifle these days, at least Army-side is a stock M4 Carbine with a Grippod and an M150RCO/PVQ-31B firing whatever ammunition the unit is issued (be it M855 or M855A1), lights and lasers also based on what the unit issues.  

~Augee

The first "SDM" rifle I saw (and then used) was just a command-authorized alteration to some M4 carbines.  It had a KAC free-floating forearm, ACOG (TA01NSN), a stainless barrel, and a service rifle trigger.  
This was Mosul and Fallujah circa 2004.

In Afghan, my unit had a mix of MK12's and M27's (HK 416). We left the MK12's there and now we just use M27's for our DM's

Thank you for the rifle info.And,thank you for your service.

I went to the school with a regular M16A4 and ACOG. In country we got M14's, the story behind it were they were the honor guard's M14's they used for drill that were refurbished to function again. Not sure how true it is.

UNNS for the Mk12 did not acquire enough to equip all the GCE, so Arty and MPs mostly had to use M39s

Getting M39s at Camp Lejeune to do PTP for 10th Marines units was next to impossible because there were not any to be had because they were all overseas.

I never saw any MK12s in country. I was SDM and me and my company's SDMs had M14 EBRs with Leupold MK4s. When did they start issuing this new SDM rifle?

We fell in on some Mk12s once we got to our little Fire Base, but we transferred the M39s over to 1/12 shortly before we deployed, from 3rd Marines SS. As far as I know, we were the first unit to fire the ones that we got after they shipped to the fleet, so that was kind of cool. Also, thanks for the info you provide on these sort of things R0N, it is always interesting brother.

From what I can tell, Mk 12s are mostly a Marine thing as far as conventional forces go. We got our M39s in March 2011 or so before we deployed, if you're asking me this question.

I tried to get them to train 1/10 to prep them for deployment, I cannot remember if I remember right they would be RIPng with but 3/10 who replaced 3/11

We replaced 1/10 when I got in country, some how we probably got the gear yall were after. The whole M39 thing was weird how all of a sudden we were told that DMs wouldnt be getting Mk12s and would be getting M39s instead, then there was a rush to familiarize with them like a week before we left. No M14 mag pouches were issued or anything so we were scrambling to get that gear lol.

That's what I figured also. We all had M39s. I loved that gun. I got mine Nov 2011 as did the rest of our guys. Exceptional weapon system if you ask me.

I was Army infantry ABN btw.

M39.is a little bit different than the M14 EBR used to the Army

Ok thanks for clearing that up, I actually googled M39 after seeing it in this thread bacause I had never heard it before, and what popped up LOOKED like the m14 EBR I had in Afghanistan. Never calling the rifle I had carried anything other then my m14 I figured after seeing it in this thread The Army had 're designated it the M39, just no one actually called it that.

So what's the difference between the M14 EBR I carried and a M39?

Afghanistan Dec 2011

I expect a correction will come, but I was under the impression the Army EBR's were worked by Smith Enterprises and Rock Island Armory, while Marine M39's are done by the PWS @ Quantico using the old M14 DMRs. There are probably further distinctions between the actual Sage chassis used, barrels, etc.

I think this is correct, I seem to remember when I got mine talking to the company armorer he said they came from rock island.

One of the gun mags had a whole spread on the Army EBRs, the whole process with the armorers hand checking the inbound guns, and by the time they went outbound they were works of art. Lots of attn to detail, QC, etc. They also showed SEI doing a bunch of stuff as part of the process.

Better yet, DTIC article
DTIC Article on M14 EBR and M39

The M14 EBR and M39 EMR were both stop gap measures, both ground services are replacing all of them

That's really awesome

Now that I have the new scope on the rifle I tried it again at 500 yards. My loads were badly pulled M-855 Ball bullets over 25 grains of WC-846,CCI SR primer once fired mixed 5.56 brass.
Wind was inconstant left to 1-5 mph. I fired a 30 round magazine at one second intervals. All rounds landed on target. The new barrel in breaking in nicely.
I would not of thought the bullets wit hthe "tractor" pull marks would shoot that well.

I just got issued a sopmod stock and an acog when everybody else had aimpoints. SDM in Afghanistan 2006-2007.

Honestly if I was in Afghan i'd rather have the ACOG considering how tali-whackers fight. Talking with my best friend right after his last deployment he said most of his engagements were at 500-800 meters. Anything past 400 is where I would start needing magnification even with 20-20 vision

Some of the 82nd guys had EBR's. I never saw anything else of ours that was SDM-ish.