Reloading the 7.62×39 mm Russian: Load development with 125 and 150 gr. bullets
Arguing online about 1911s versus Glocks, ARs versus AKs and 5.56×45 NATO versus 7.62×39 Russian cartridges is about American as apple pie. For many, the stubby Russian cartridge developed a reputation for being “superior” to its Western rival, the 5.56×45 NATO. While the Soviet Army may not agree (they went 5.45mm back in mid-70s), the 7.62×39 Russian is certainly here to stay.
Often encountered in an AK or SKS type semiautomatic rifle, the 7.62×39 mm is also available in conventional bolt action offerings, the CZ 527, Ruger 77 (limited run) and Howa MINIACTION, to name a few. As I had discussed in my review of the Howa MINIACTION, I’ve been chasing the 7.62×39 white whale for years. The very concept of a low recoil 30-caliber plinker with plenty of cheap steel cased ammo makes me lose sleep, at one point I even made a custom M700 for it (I painted it red since it was a commie cartridge).
The things that make the 7.62×39 mm successful in AK and SKS rifles make it burdensome in a bolt action rifle; a short case, tapered body, low powder capacity, and anemic external ballistics. Theoretically, it should be one of the most accurate cartridges available. It did give rise to the 220 Russian, a 22 caliber center fire cartridge that uses a necked down case with a small rifle primer. The 220 Russian in turn gave rise to the 6PPC, which is a necked up 220 Russian and perhaps the most accurate 100 and 200 yard cartridge in the world. It doesn’t stop there, neck your 6PPC up to 6.5 and guess what you have? A 6.5 Grendel (I always call it a 6.5-7.62×39 mm to get the Grendel guys upset).
Since the 7.62×39 has been around for years and is produced throughout the world, consistent manufacturing standards are hard to find. Guns will have groove diameters from .308-.311″. Bullets will have diameters from .308 to .312″. Factor in the relatively low concentricity of steel cased ammunition and finding a match that works well can be a chore. Every now and then you’ll find a guy (normally a benchrest shooter) who builds a custom 7.62×39 that shoots insanely well. These guns typically have a .308″ groove diameter and slower twist rate than the 1-9.45″ you’ll usually encounter (think 1-12″ to 1-14″). SAAMI specifies a bullet diameter of .311″- .002″, and a groove diameter of .310″ (see page 53 of this link).
The 1-9.45″ (240mm) twist rate of the 7.62x39mm Russian is undoubtedly one of its bigger accuracy pitfalls. Most literature reports the longer 150 grain flat base bullets being stabilized with a 1:15″ twist for the velocities obtained with this cartridge. As a rule, too fast a twist rate will exacerbate any concentricity issues with your ammunition and potentially lead to a degradation of accuracy.
For reasons I don’t quite understand the 7.62×39 is often compared to the 30-30 Winchester. In similar weight bullets, the 30-30 tends to outperform the little Russian cartridge. A better comparison is to the 300 BLK loaded with a comparable 125 gr. bullet. In this case, the cartridges have a similar bullet weight and diameter with similar velocities with the 7.62×39 typically edging out the BLK with comparable 125 gr. loads.
While the majority of 7.62×39 ammunition you’ll encounter is steel cased and cheap, you can find brass cases that are reloadable. In order to stretch every last bit of accuracy out of my Howa MINIACTION, I decided to start with brass cases. If I’m using brass, might as well go with the best cases I can find, Lapua.
For purposes of this post, I’ll be using a Howa MINIACTION chambered in 7.62×39. A few points. First, it is a bolt action rifle. I don’t have to worry about parts from mysterious third world sources so I feel comfortable pushing hotter loads. I would NOT use any of these loads in a semiautomatic and suggest consulting a load manual prior to development. Second the Howa, has a .311″ groove diameter and 1-9.45″ twist. For me, this means .308″ bullets are off the table; although some will report acceptable results with a .308″ bullet in a .311″ bore.
To get the MINIACTION ready for the range, I installed a TRACT Optics 3-15x42mm TORIC scope in Warne rings and bases (also from TRACT). This scope is a perfect fit for a rifle like this; providing a wide range of adjustment, having adjustable parallax, and a compact size. When you pick up the rifle, you know you have a good combination. I’ve been using TRACT scopes for the past few months on my hunting and sporting type rifles and have been pleased with the balance of performance, clarity and value. A solid option.
Before we start talking about reloading please take the time to read the following disclaimer:
WARNING: The loads shown are for informational purposes only. They are only safe in the rifle shown and may not be safe in yours. Consult appropriate load manuals prior to developing your own handloads. Rifleshooter.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.
Bullet selection was fairly simple since I needed .311″ diameter and like Sierra bullets; that meant I was going to use the 125 gr.(above, right) and 150 gr. Pro-Hunter (above, center) soft points (SPT). As with any small capacity case that isn’t very overbore (underbore?), powders tend to have faster burn rates. For this post I’ll be using Hodgdon’s new CFE BLK which was developed specifically for the 300 BLK, as well as BL-C(2), H4198 and H322.
I used a new tool to prime the cases: the Competition Primer Seater (CPS) from Primal Rights. This is a high-end, high-volume tool designed for shooters who reload a lot. While it may cost more than most other systems, I have been thoroughly impressed with it so far (to check it out click here).
For dies, I used a Hornady 2-die set. Each Hornady 7.62x39mm set comes with two expanders, one for .308″ bullets and one for .311″ bullets. Since Lapua brass comes sized for .308″ bullets, you might consider running an expander through the neck prior to loading .311″ bullets.
All shooting was conducted prone, from a bipod with rear bag. Velocity data was recorded with a MagnetoSpeed barrel mounted ballistic chronograph.
Before we start looking at how reloads performed, let’s take a look at how the rifle shot with factory ammunition.
With factory ammunition, note velocities for the 122-123 gr. projectiles ranged from 2,247 to 2,512 feet/second and group size ranged from 1.399″ (1.336 MOA) to 3.275″ (3.128 MOA).
The 154 gr. Tula soft point load clocked in with a velocity of 2,164 feet/second and a group size of 3.273″ (3.126 MOA).
Results for the 125 gr. Pro-Hunter are shown below:
125 gr. Pro-Hunter H4198 loads ranged from 2,287 to 2,349 feet/second with group sizes ranging from 1.976″ (1.887 MOA) to 2.865″ (2.736 MOA).
125 gr. Pro-Hunter BL-C(2) loads ranged from 1,985 to 2,054 feet/second with group sizes ranging from 2.121″ (2.026 MOA) to 5.249″ (5.013 MOA).
Average group size for all loads tested was 2.110″ (2.016 MOA).
Clearly, for the 125 gr. Pro-Hunter, the best mix of velocity and precision came from the CFE BLK. BL-C(2) was by far the worst powder in terms of velocity and precision. The published load data showed much higher than measured velocities for the loads given. H4198 worked better than the CFE BLK and would be a good second choice in powder for the 125 gr. bullet weight.
Results for the 150 gr. Sierra Pro-Hunter
150 gr. Pro-Hunter CFE BLK loads ranged from 2,129 to 2,210 feet/second with group sizes ranging from .272″ (.260 MOA) to 1.685″ (1.609 MOA).
Average groups size for all 150 gr. Pro-Hunter loads tested was 1.439″ (1.375 MOA).
As with the 125 gr. loads, the CFE BLK made a strong showing with the 150 gr. loads and are responsible for a mind boggling three shot .272″ (.260 MOA group) and velocities close to those obtained with H322. The first group was only three shots because the rifle was zeroed for the 125 gr. SPT and the point of impact (POI) for the 150 gr. Pro-Hunter was 10″ away from the POI for 125 gr. load at 100 yards! I fired the first two rounds over the top of the IPSC target that I used as a backer. I would suggest both the CFE BLK and H322.
I ended up testing a total of 35 different factory (5) and hand loads (31) with bullets ranging from 122 to 154 gr. in weight. Hand loading was able to produce higher velocities as well as more precise ammunition. If you have a .311″ groove diameter 7.62×39 bolt action rifle, I would take a look at the 125 and 150 gr. Pro-Hunter with CFE BLK and H322 powder. I think that’ll point you in the right direction.