So, what’s a fella’ to do when he likes the AR platform but does not like the 5.56x45mm/.223 cartridge but does like the 7.62x39mm cartridge but does not care for the AK platform? Some would say to replace the upper of a MSR with a 7.62x39mm upper. But, there are also some other consideration than just replacing the upper, and I don’t like to mix-n-match. The most logical solution is to simply have an MSR platform that is chambered for the 7.62x39mm cartridge straight from the factory. That is exactly what was done.
There are several manufacturers of NSR platforms chambered in 7.62x39mm in the market place. My first MSR platform was from Windham Weaponry, the “SRC,” chambered in 5.56x45mm/.223, and which has proven itself worthy. I felt that another Windham Weaponry MSR platform would not be any different. Thus, my “MSR47” project began with the “Windham Weaponry 7.62×39 SRC.”
Windham Weaponry answered the call of shooting enthusiast like me for a mid-range cartridge like 7.62x39mm to be run through a platform in which it was not intended to run. There had to be some changes, of course, for that cartridge to perform flawlessly in an unintended platform. The chamber mouth had to be widened, a beefier bolt was called for, and a different feeding system (magazine). The bolt face must be relieved to accept the base of the 7.62x39mm cartridge and a little more “oomph” is required to provide positive ignition with hard cartridge primers like that found in “Foreign” ammunition. And last, but not least, the gas port has to be enlarged to handle the 7.62x39mm cartridge properly. Otherwise, the AR platform pretty much remains the same as with the 5.55x45mm/.223 cartridge versions, including the buffer and buffer spring.
Of course, arguments can be had as to why I chose Windham over, say, the CMMG MK4 (which uses standard AK47 magazines or equivalent), or the Rock River Arms (LAR-47 X1), or even why the 7.62x39mm cartridge over the .300 Blackout (7.62x35mm). All I can say is, well, personal shooting preference and a healthy investment in things 7.62x39mm. If a .300 Blackout actually entices me, it is s simple matter of changing out the AR15 platform. Anyway, back to the ‘Windham Weaponry 7.62×39 SRC.”
I admit that there is a bit of a risk in purchasing a firearm that was not intended to chamber tapered cartridges like the 7.62x39mm. The 5.56x45mm/.223 is a straight-walled cartridge, as is the .300 Blackout, as is the 7.62.51mm/.308 cartridges. Admittedly, the 7.62x39mm cartridge is better served in firearms designed to chamber it like the SKS, AK47 and platforms different from the standard AR. There seem to be no problems with bolt-operated firearms, because of the obvious manual chambering. The taper of the 7.62x39mm cartridge in MSR platforms seems to have caused some consternation among those who, like me, favor the cartridge and would like to favor it more in an MSR platform. But, I did have confidence in Windham Weaponry’s efforts in solving the 7.62x39mm MSR incompatibility issues.
The “SRC” in the nomenclature indicates that the platform is “Sight Ready” that essentially means that it has no sights but does come equipped with a flat-top rail in which fixed and optical sights can be mounted – and it is a carbine-length firearm. For fixed sights, a set of MAGPUL PRO front and rear sights are recommended. The Gas Block sight mount requires that a metal sight be mounted, since it can get very hot during hard running. While I don’t worry about that, I opted for the MAGPUL PRO sights anyway, as these are the same that is on my other version of the platform.
For non-magnified and magnified optics there is a range of options that can boggle the mind and leave one confused. Being less confused than I was a year ago, and for functionality testing, I mounted a Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope that I had mounted on the Windham Weaponry “SRC” in .223/5.56.45mm and placed a Nikon P223 3×32 in its place. The Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope is one of my favorite magnified optics, somewhat compact scope that has been mounted on several of my rifles including the Ruger Ranch in 7.62x39mm. I have come to appreciate the eye relief that this scope provides with fixed stocked long guns and felt that with an adjustable stock like this carbine has that eye relief would not be an issue. The scope was mounted with my favorite Warne scope rings of “high” height to sufficiently clear the rear MAGPUL sight (when I install it) and the charging handle. But, before I get buried too deep in attachments, let’s look at the Windham itself.
The “Windham Weaponry 7.62×39 SRC” is the typical semi-automatic, gas impingement system that we all know and of which we have a love/hate relationship. The trigger pull, as with most COTS MSR platforms leaves a lot to be desired. Windham has installed an “assist” hammer spring to help with reliable ignition. It is not a target trigger by any stretch of the imagination.
The Carpenter 158 steel bolt is substantial but all the “slidey” work done by it works flawlessly. Extraction and ejection is positive with expended shells being expelled from the chamber without issue; something that we left-handed shooters look forward to. Due to the larger case diameter, the bolt and extractor are unique – and caliber specific – to the Windham Weaponry 7.62×39 SRC. The bolt is identified by three rings machined into the body behind the lugs. Internal bolt carrier parts; however, such as Gas Keys, Gas Key Screws, Firing Pin and Firing Pin retaining Pin, are standard “AR” parts. The extractor does not use the extractor o-ring commonly found on AR rifles. – source: Windham Weaponry.
All other controls, the safety, bolt release, forward assist, and magazine button are in their respective locations. A receiver dust cover is also part of the package. There is nothing new to learn here.
The receiver finish if hard-coat black anodized. The receiver is a forged 7075 T6 aircraft aluminum unit with aluminum trigger guard.
The “Windham Weaponry 7.62×39 SRC” comes with one thirty-round magazine from D&H Industries out of Oconomowoc, Wisconsin. I find the thirty-round magazine cumbersome for most of my uses, and I will probably order a few 5-round, 10-round, and 20-round magazines for general use while ordering a few more 30-round magazines for “Critical Duty.” The provided magazines seats firmly into place and drops free just as nicely. Unlike the AK, simply insert the magazine straight up and in; there is no “mag rocking” as with the AK.
The magazine is, of course, different from those used for 5.56.45mm/.223 ammunition. The familiar AK “Curve” is present in the 30-round magazine and diminishes the shorter the magazine being used. The AR 7.62x39mm magazines, while not proprietary, are different and a few sources other than Windham provide them. Windham Weaponry relies on the CD magazines, but there are A. Stoner magazines available as well, of which two 10-round and one 30-round magazines were ordered, as was an UpLula loaders for AR 7.62×39 magazines. Only use of both will tell which the better magazine is.
The pistol grip is an A2 black plastic grip that will soon be changed out for my favorite Hogue grip at some point.
Upper to lower lock-up is tight. I have had to use an Accuwedge on other MSRs. This small wedge-shaped piece – molded of high-density, thermoplastic rubber (½” / 12.5mm long) instantly tightens loose upper & lower receivers and stops rattling. However, it was not needed in this case. The only looseness felt in this firearm is the adjustable stock.
Windham Weaponry offers a ‘field repair kit” that consist of: a 7.62×39 Firing Pin (note the groove around its head for 7.62 identification); a Firing Pin Retaining Pin; Bolt Cam Pin; 7.62×39 Extractor Cartridge; Extractor Pin; Extractor Spring; Extractor Spring Insert; a set of 3 Bolt Gas Rings; Hammer and Trigger Springs; Disconnector Spring; Hammer and Trigger Pins; a Front Sight post (the taller .040” height); an A1/A2 Front Sight Adjusting Tool; and a CP-02 Chamber Plug/Safety Tool. As I have “field repair kits” for other AR platforms, I felt that this one would be a good investment, considering the caliber of the firearm.
The stock is a 6-position telescoping unit, not unlike those found on most COTS MSR platforms, which means that the “slidey’ part is loosely-fitted to the buffer tube housing. These are not my favorites and will be replaced with a “rifle-length” buffer, buffer tube, and spring and a MAGPUL MOE fixed stock for a more solid feel of the firearm. A fixed sling loop is provided, as is a webbed strap that serves as a sling, or so it is claimed.
The 16” chrome moly vanadium barrel is 4150, a 1:9.5” right-hand twist with four lands and grooves and capped with an A2 “birdcage” flash suppressor. Threading is 5/8×24.
The hand guard is a M4 double-heat shield that is classically attached with the typical AR locking ring. I do have to say that the Ruger AR556 does have a good feature with the ‘screw-type’ locking ring, but this is not a Ruger and Ruger just may hold the patent on that feature.
The front Picatinny rail gas block is ready for your favorite sight – as long as it is metal. As I mentioned previously, the MAGPUL Pro sights will be selected to adorn the firearm as a back-up to the magnified optic. The MAGPUL Pro sights are rugged, but lack the push-button flip-up feature.
The gas block also has a sling loop and bayonet lug, the latter being the most important, of course.
With the Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope mounted, and two boxes of Fiocchi 124-grain FMJ (brass case), it was time to do a quick evaluation of the “MSR47.” The AR Stoner magazines (a 30-round and three 10-rounds) had come in. I was interested in comparing magazines as much as I was cartridges. The Maglula UpLula loader for the AR 7.62×39 magazines makes loading magazines a breeze.
The provided D&H Tactical, 30-round magazines seems to be of better quality and construction than the AR Stoner products, and they are more costly than others, but the real test is in the shooting.
While there should be no problem running steel-cased ammunition, Windham Weaponry recommends shooting only brass-cased cartridges for breaking in the firearm – at least 100 rounds of them. Which is fine with me, as steel-cased ammunition would be for the “last duty call” if need be. Besides, I have firearms that will fire the steel-cased ammunition just fine, thank you.
While twenty-five yards is no real test for a MSR, I was more interested in function, but I hoped for “reasonable” accuracy as well. The Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope helps me see what it is that I aiming at, but it is up to me and the Windham to see little holes appear at that point of aim.
With a zero at twenty-five yards, with this ammunition, the MPBR (Maximum Point Blank Range) stats are pretty impressive. The MPBR would be somewhere in the vicinity of 258 yards, considering an 8-inch target. This means that one could shoot out to this distance (or so) and the bullet would remain in an 8-inch “window.” This explains why the 7.62x39mm cartridge is considered as a COM (Center Of Mass) cartridge when chambered in a SKS or AK47 platform. Consider that at one-hundred yards the round would impact around 4-inches high from POA (Point Of Aim). The vital zone of a deer (and man, incidentally) is roughly 8-inches. This means that if you aim center mass, you are going to hit something vital out to a distance that is within the MPBR, if everything contributing to that shot is desirable. The 7.62x39mm cartridge has been compared to the Winchester .30-30 cartridge. I believe that it is closer to the .300 Blackout (7.62x35mm), but with better ballistics. In my line of thinking, the 7.62x39mm cartridge is almost the perfect mid-range cartridge, and the Russians do to, apparently, with the exceptions of the 5.45×39mm cartridge that replaced the 7.62x39mm cartridge. But, I’ll quit digressing and get back to the “MSR47.”
As I mentioned earlier, the trigger is a challenge being heavy in pull-weight, but it does have little creep and it does have a crisp let-off. Being new, the trigger is somewhat gritty, but not as bad as I expected from a stock MSR trigger. Trigger pull weight averaged 7.9 pounds on this unit
With the Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope mounted on Warne rings, the centerline of the scope is approximately 2.25-inches above the center-line of the bore. I was shooting for a 100-yard zero at 25twenty-five yards. With a minor adjustment for windage, holes started appearing about 0.5-inches above POA. Close enough to a 100-yard zero for me.
I wish I could say that range time went without difficulty, but I can’t. The “MSR47” was stiff, as were the magazines, and multiple attempts with the bolt picking up rounds from the magazine failed – at first. Several of my shooting companions fired the “MSR47” and also experienced the bolt not picking up a cartridge. I don’t fault the “MSR47” but I do fault the magazines. However, I was able to fire all cartridges in the D&H magazine and all ten cartridges in each A.R. Stoner 10-round magazine as the shooting session was near to ending. The bolt did lock back on the last round for each magazine. I realized that I may have been resting the “MSR47” on the rear tip of the D&H 30-round magazine, which would have caused the rear to tip downward, which would explain why a cartridge was not being picked up, as the bolt would have rode over top of the cartridge. I also had to make sure that all cartridges were seated against the rear of the magazine, as this might also cause the bolt to slide over top of the next cartridge. I also had to ensure that the magazines were fully seated in the magazine well. The last forty rounds fired went without incident, the bolt locked back on the last round, and I was starting to feel good about the “MSR47.”
Felt recoil was minimal. The MSR platform helps to soak up what little recoil the 7.62x39mm cartridge exhibits. I could shoot the “MSR47” until the cows come home. Shooting was done with no rest except one elbow on the shooting bench top to somewhat steady things, as it might be resting on a tree limb or other platform out in the field. The Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope, while not a target scope, is perfect for this type of shooting. Simply put the little round circle of the scope on what you want to hit, and if little round holes appear on the target within the little round circle in the scope, you can consider it a good shot. Since I was aiming for (no pun intended) a one-hundred zero, holes appeared just above the circle enough to clear out the “X” and I consider that good enough for “opening day” of the “MSR47.”
The shell deflector works just fine, thank you and kept ejected cases away from my face. Extraction and ejection was positive. Hopefully, any feeding issues will disappear after the “MSR47” and magazines are broken in.
Primer strikes were positive with indention centered and of sufficient depth for positive primer ignition.
As expected with any “direct impingement” firearm, the upper assembly becomes quite fowled even after a short shooting session.
Personally, I use Brakleen (and plenty of ventilation) to de-grease the bolt and bolt carrier, a .410-gauge bore mop to clean the bolt recess, and a .308 bore-snake and Ballistol for quick bore cleaning (short-term storage only). A light coating of white-lithium grease takes care of the hammer face while the bolt carrier receives white-lithium grease on running surfaces with a light application of Wilson Combat Ultima-Lube II oil taking care of the rest of the bolt carrier. Bolt lugs also receive a treatment of white-lithium grease. A tube of Wilson Combat Ultima-Lube II oil is also in the range bag, just in case I need it. I don’t run my firearms hard, but I am prepared to do so if necessary.
Future and personal modifications will include:
- Timney trigger to reduce the pull weight.
- A Hogue finger-groove pistol grip.
- MAGPUL PRO front and rear sights.
- MAGPUL OEM Fixed Rifle Stock.
A Bore Store SRC-2 and range bag specific to the “MSR47” has been ordered, in addition to two 30-round D&H Tactical magazines and “field repair kit.”
I am highly-satisfied with the Sightmark Core HX 2-7x32mm HHR Hog Hunter Riflescope mounted on Warne rings and can think of no need to change them.
The Total Package:
Weighing in at 6.15 pounds without the magazine, the 32.375-inch (36.125” with stock extended) just seems to be another run-of-the-mill AR platform that is chambered in a caliber most often associated with the venerable AK platform, but has actually been in service since 1944, and there is no dispute as to the effectiveness of the round – and the cartridge has been used in many disputes.
Commercial Russian-made 7.62×39mm ammunition, such as those sold under the Wolf Ammunition brand name, are also available in full metal jacket (FMJ), soft-point (SP) and hollow-point (HP) variety. The SP bullets offer improved expansion. American-made ammunition, such as Federal Fusion offers increased usage of the cartridge for small to medium game, and characteristically is compared to the .30-30 cartridge as a mid-range cartridge.
Bolt guns like the CZ-527 and Ruger American Ranch are excellent choices for the cartridge as is the Ruger Mini-30.
In addition, several AR-15 manufacturers have produced the 7.62x39mm option. Some current and past companies include AR-Stoner, Armalite, Colt, Rock River Arms, Olympic Arms, DPMS, Del-Ton Inc, and ModelOne Sales. Wide availability and low cost ammo with a wide variety of manufacturers make it a much lower cost of operation compared to other 5.56x45mm alternatives.
My choice was the Windham Weaponry R16M4FTT-762 because of my past experience with the 5.56x45mm/.223 version of this firearm. Windham Weaponry has an interesting history. Formerly know as “Bushmaster” the company has risen from the ashes, so to speak, to again bring high-quality yet affordable AR platform firearms. They are great people to talk with and immensely helpful should you have an issue with your “Windham.”
The Final Word
Should you, like me, favor the 7.62x39mm cartridge and the MSR platform, the Windham Weaponry R16M4FTT-762 is an excellent marriage of technologies. This little carbine does what it is supposed to do, something that I cannot say yet about the magazines. However, with everything being new, some glitches were expected (if you expect them), and with time and use I can see these glitches being things of the past.
- Model: R16M4FTT-762
- Caliber: 7.62 x 39mm
- Action: Semi-Automatic, Gas Impingement System
- Capacity: 30 + 1- Ships with one 30 Round Magazine (accepts all std. sizes)
- Safety: Manual Lever with Indicator Markings on Both Sides of Receiver
- Receiver: M4A4 Type Flat Top Upper Receiver
- Receiver Material: Forged 7075 T6 Aircraft Aluminum with Aluminum Trigger Guard
- Receiver Finish: Hard-coat Black Anodize Finish
- Bolt Material: Carpenter 158 Steel
- Barrel: 16” M4 Profile, Chrome Lined with A2 Flash Suppressor
- Barrel Material: 4150 Chrome Moly Vanadium 11595E Steel with M4 Feed Ramps
- Rifling: 1 in 9.5” – Right Hand Twist
- Stock: 6-Position Telescoping Buttstock
- Forend: M4 Double Heat Shield Hand guards
- Pistol Grip: A2 Black Plastic Grip
- Rear Sight: None – Ready for optics or other accessory sights on Mil Std 1913 Rail
- Front Sight: None – Mil Std 1913 Rail Gas Block – Ready for accessory sights
- Weight / Length: 6.15 lbs. (without magazine) / 36.125” (32.375” with Tele-stock collapsed)
- Packaging: Hard Plastic Gun Case with Black Web Sling & Operators Manual
Update 08/12/18 – “The Short of it.”
Items mentioned in the original review were either added or replaced:
- The 6-position stock provided by Windham Weaponry was replaced with a Leapers UTG AR-15 A2 Style Fixed Stock Assembly Polymer Black RB-T469B (see, References), which affords me a more stable platform from which to shoot the MSR. I may opt for the MAGPUL MOE stack at some time, but that decision has yet to be made, since the A2 stock seems to be just fine.
- The standard A2 pistol grip was replaced with the Hogue AR-15 OverMolded Rubber Pistol Grip With Finger Grooves and Beaver Tail Black 15020 (see, References).
- MAGPUL Pro sights were added front and rear for BUS.
- An “Accuwedge” was added to minimize the amount of play (which is very little) between the upper and lower.
And, now for the bad! The “MSR47” still exhibits FTFs (Failure To Feed). However, this may be a break-in issue rather than a defect with the firearm. Only time and use will tell; however, let me back into this a bit.
It seems as though the bolt is “short stroking.” While extraction and ejection is positive, the top round in the magazine is not being picked-up by the bolt. During the first firing session, the time between FTFs was decreasing as the firearm was being shot, perhaps due to the magazine and buffer springs being broken in. With the new A2 rifle stock and two new magazines, the FTF issue raised its ugly head again. Again, the FTF issue may be because of the new (longer) rifle-length buffer spring and the new magazine follower springs. I should have changed only one thing and evaluated that one thing. In short, the timing if off.
FTF indicators were that; (1) the bolt was not picking up the top cartridge, (2) the bolt was starting to pick up the top cartridge, but rode over top of the cartridge; thus, preventing the cartridge from fully chambering, (3) the bolt was not fully sliding out of the bolt carrier during recoil, due to new gas rings and/or new Buffer Spring, (4) the magazine was not fully seated and/or positioned correctly to allow the bolt to pick up the top cartridge. However, the bolt was not locking back after the last round, which indicates that the bolt is not coming back far enough to clear the “lock-back-on-last-round” feature of the magazine, thus preventing the Bolt Catch from engaging the bolt. Manually pulling the Charging Handle to the rear far enough to chamber a cartridge was not a problem. The floor plate of the magazine is definitely catching the “lock-back-on-last-round” Bolt Catch when the bolt is manually cycled. So, we might be talking about a bolt “inertia” issue. Note that we are only talking about approximately 0.25-inch of rearward travel when the bolt is locked by the Bolt Catch and when the bolt is fully at the end of its travel (seated rearward against a fully compressed buffer spring).
I suppose that gas pressure could enter the equation, since the rearward gas must be sufficient enough to properly cycle the bolt – move the bolt carrier rearward enough to overcome the buffer spring tension and clear the top cartridge in the magazine and Bolt Catch. Since FTFs were decreasing during the first shooting session, I am going to go with the issue being with a new buffer spring being in the A2 stock. If I am correct in my assumption, I should see less and less FTFs as the new buffer spring wears in.
Now, I have to admit that I am not one to saturate, like some, the bolt carrier and bolt assembly with lubricant. The bolt carrier and bolt were lubricated prior to assembly, but the gas rings do not have wear and the bolt assembly is certainly sealing within the carrier. I think that I am going to be increasing my lubrication of the bolt carrier and bolt assembly.
Now, what may also be causing the issue is the ammunition itself. Fiocchi 124-grain FMJ is rated at 2330fps at the muzzle. The 123-grain HP Golden Bear (brass-plated steel case) 7.62×39 is rated at 2460fps. That 100 or so difference in feet-per-second,could make a difference.
While speaking with my shooting companion about the issue, he was reminded of a time when another shooter, who had a custom-made MSR, who was having a similar issue, switched from a .223 cartridge to a 5.56x45mm cartridge. The FTF issue went away. Apparently, the 5.56x45mm cartridge, with its higher chamber pressure and velocity, was enough to make a difference in the firearm cycling properly.
So, at the next range session, I will be trying the 123-grain HP Golden Bear (brass-plated steel case) 7.62x39mm ammunition to see if that ammunition makes a difference. And, to tell the truth, I hope that it does, because I could then use the same ammunition for the AK, the SKS, and the Ruger “Ranch’ carbine and simply life.
There has been only 160 (brass-cased) cartridges run through the “MSR47” thus far, and this firearm may require more break-in time than the same version of the firearm in 5.56x45mm/.223, of which I have not (so far) had feeding issues. I have to say that with the SKS and AK47 firearm, feeding is usually not an issue due to the looser tolerances of these firearms compared to the MSR platform.
- “Windham Weaponry 7.62×39 SRC”: https://www.windhamweaponry.com/law-enforcement/caliber/762-39-caliber/
- SOOTCH00 Review: https://www.youtube.com/watch?v=_zPHac8Vvi4
- D&H Industries (30-Round Magazine): https://dh-tactical.com/product/762x39mm-caliber-ar-15m-4m-16-pattern
- Magpul MBUS PRO Steel Sight Set MAG275 & MAG276 BLACK: https://www.amazon.com/gp/product/B00CLGLRD0/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
- Sightmark Core HX 2-7×32 HHR Hog Hunter Riflescope: https://www.amazon.com/dp/B01AHQA8AS/?coliid=I38VLFMDTD22PY&colid=Q8X6JBTGBISS&psc=0&ref_=lv_ov_lig_dp_it
- Magpul MOE Rifle Stock Black: https://www.magpul.com/products/moe-rifle-stock
- Leapers UTG AR-15 A2 Style Fixed Stock Assembly Polymer Black RB-T469B: https://www.cheaperthandirt.com/product/ar-15-a2-fixed-buttstock-complete-assembly-utg-black-storage-compartment-4712274529861.do?sortby=ourPicks&refType=&from=fn&ecList=7&ecCategory=479164
- Hogue AR-15 OverMolded Rubber Pistol Grip With Finger Grooves and Beaver Tail Black 15020: https://www.cheaperthandirt.com/product/hogue-ar-15-overmold-grip-with-beavertail-and-finger-grooves-rubber-black-15020-743108150207.do?from=Search&cx=0