By Rob Kay and RN Price
Back in February of this year we had the opportunity to test and evaluate the Headhunters Firearms HH762 (7.62×39) upper receiver. We liked it after our initial review and after nearly ten months, and who knows how many rounds later, our judgement is still the same.
That said, there were several modifications we had to make both on the upper and lower receiver that were necessary to effectively use this unit.
The 7.62×39 Round
The 7.62×39 cartridge is perhaps the most popular (and iconic) in the world because of its association with the Kalashnikov assault rifle. It’s a great round within its range envelope, especially effective out to about 200 meters. It’s effective with a multitude of game. Roughly equivalent in energy to the Winchester 30-30, on the range it will really make a steel gong dance — especially when compared to the typical 5.56×45/.223 bullet.
Over the years a number of manufacturers have built 7.62×39 AR-15 uppers but this round was never really intended to be used with an AR-15. Therein lies the source of the concerns surrounding this particular chambering on an AR.
In the past, perhaps the most significant problems encountered with the 7.62×39 AR-15 design has been feeding, bolt durability and unreliable ignition.
The first two factors were not a problem with the HH762. We can’t recall one failure-to-feed jam with this product. One of the main reasons was that there are now first class magazines available for this platform. We tested products from ASC (Ammunition Storage Components) out of New Britain, CT and C Products Defense from Bradenton, FL. Both brands worked flawlessly. We’d highly recommend either brand.
The upper also was flawless in its operation. There was one failure to completely eject a cartridge. For 10 months of shooting, that’s not too bad.
Bolt durability (to date) has not been a problem.
Enter the Geissele Super Semi-Automatic (SSA) Trigger
The main issue with using this upper was unreliable ignition. The origin of this problem begins with the style of primers coming out of Russia and Eastern Europe which are notoriously hard compared to what’s produced in this country. AKs have quite robust springs on their fire control group which provides the necessary force needed to ignite these rigid primers.
The average AR-15 fire control group does not have the same “striking power” to consistently elicit a bang from this type of ammo.
It’s unfair to blame Headhunters, who after all produce the upper receiver. They are not responsible for wimpy trigger groups.
We tried several varieties of AR-15 triggers but couldn’t get reliable ignition. We replaced the stock spring inside the module of a popular trigger with a stronger specimen but that still wasn’t enough to consistently work.
We sought advice from our friends at Geissele Automatics, the well-regarded trigger manufacturer out of North Wales, Pennsylvania. They confirmed that the power of the AR hammer is a huge factor with ignition issues and suggested that we experiment with their SSA trigger.
The SSA has a pull weight of about 4.5 lbs, which consists of 2.5 lbs on the first stage and 2 lbs on the second stage. Geissele builds these for US combat units and the trigger system is suitable for a variety of modes such as Close Quarters Battle (CQB), mid-range carbine work and, for Squad Designated Marksman (SDM) rifles. Despite this latter category, Geissele states that the SSA is not a “match” trigger because the second stage breaks like a carrot rather than an icicle.
I think we can get caught up in semantics here!
We added the Giessele SSA in about ten minutes, and whether it breaks like a popsicle or crystal glass, this is one fantastic trigger. Just as importantly it had a very robust spring. Mind you, this fire control group still didn’t match the fierce snap of the AK hammer but it certainly approached it.
It solved about 95% of the problem. The ammo went bang most of the time, but still not quite all of the time. There was one more factor to consider—the firing pin.
We acquired a so-called enhanced firing pin, designed specifically for the 7.62×39 and 5.45×39 rounds. These pins are designed to move slightly more forward than the stock pin and thus penetrate those stubborn little East European primers to a greater degree.
That did the trick.
The HH762 is a solid little performer.
Our staff has a couple of 7.62×39 uppers between us—including a Colt and a PWS. The HH762 compared very favorably to the PWS unit which costs about $1200 (just the upper!). The PWS is a high-end piston driven system but the balance, recoil and accuracy of the HH762 was similar enough to the PWS that if you were blind-folded, you’d have a tough time discerning between the two. (We’re not advocating that you shoot blindfolded but we think you get the idea).
With blindfolds off, we got about 2” out of the HH762 on our best targets at 100 yards and undoubtedly could have done better with more time and hand loads.
The Geissele SSA fire control group added a whole new dimension to the experience. The hammer spring provided the solid smack we needed for the Tula ammo and, offered a superb action, worthy of any target rifle.
Although the HH762 upper does not have pretensions of being a .5 MOA performer, having a trigger of this quality allowed us to squeeze every ounce of performance out of the upper. At $220 it’s not cheap but you certainly get what you pay for.
It transformed this rifle from “economy” to first class.
Offhand, with just iron sights, we could consistently nail an 8” gong at 110 yards. You don’t have to be Jerry Miculek with this upper (along with the SSA) to look pretty good on the range.
Ergonomics on the handguard were excellent. The rail is hemispherical and quite comfortable to hold. The upper is also well balanced and easy to point.
The only thing we didn’t like was that the Picatinny rail above the receiver had a slightly different spec than the portion over the barrel. We learned that when we placed an ADM QD mount on top for use with a red dot and it was difficult to remove. The cross-bolts got stuck in the slots but fit fine on the rail at the top of the barrel. This was the only mount where we had a problem. All the others we put on (including an ACOG) worked fine.
Not only is the quality of the build excellent, Headhunters will cerakote the rifle to your specs at no extra cost and provide a lifetime guarantee. The complete rifle (with their snazzy billet lower) is $1299.
At $599 if you’re just purchasing the upper, this is a slam dunk bargain.
Robert F. Kay, who lives in sunny Honolulu, is the author of How to Buy an AK-47.
Photos courtesy of On Target staff and Geissele.
Read more of Rob’s articles on OnTargetHawaii.com
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