With the rise of AR-47s (AR-15s in 7.62x39), steel-cased ammo has become a hot topic recently. Many people love the widespread availability and increased stopping power of 7.62x39 combined with the ergonomics and attachments of mil-spec AR-15s, but are frustrated when it does not run as reliably as standard .223 or 5.56 NATO. Here at Bear Creek Arsenal, we sell AR-15s chambered in 7.62x39 and have compiled an infographic designed to show the key differences between brass and steel cased ammo and what you'll need to make sure your AR-15 functions reliably.
Brass Cased vs. Steel Cased Ammunition
Lower price is the key and only advantage of steel case ammunition in the AR-15 platform. The price difference and availability have been further escalated by the great ammo shortage of 2021. As of now, steel case 7.62x39 can be purchased for around 40 to 50 cents cheaper per round than 5.56 or .223. In calmer times, that margin can shrink a bit, but steel case 7.62x39 is typically always cheaper than standard brass 5.56 or .223. See our Cheapest Price Per Round Infographic [Updated 2022].
A key difference between brass and steel case ammunition is the primers they use. Imported steel cased ammo like Wolf, Tula, Brown Bear, and Barnaul typically uses Berdan primers which consist of two flash holes as opposed to the cup and anvil design of boxer primers for brass case 5.56. Steel cased ammo is designed for the AK-47 and their primers are much harder than brass boxer primers. This can lead to light primer strikes as mil-spec firing pins and hammer springs often do not pierce the primer enough to cause it to light. To remedy this issue, many people add an enhanced firing pin that has a longer distance from the first “shoulder” of the tip to the very end of the firing point. This allows more of the tip of the firing pin to protrude from the firing pin hole in the bolt. Bear Creek Arsenal has begun including enhanced firing pins in our 7.62x39 AR-15s for increased reliability with steel case ammo. Additionally, a heavier hammer spring can help generate more power to cycle the harder primers reliably.
Chamber Seal, Accuracy, and "Dirtiness"
You may have heard that steel ammo runs dirtier than brass and wondered why that is the case. This is due to the expansion of the round when the gun is fired. Because brass is more malleable than steel, it expands more during firing and creates an excellent chamber seal, keeping gas from escaping around the edges of the case and instead pushing it down the barrel behind the round. Steel cases on the other hand, do not expand as much as brass cases, leading to gas escaping out the back to the BCG. This leads to lower bullet velocity (thus lower accuracy), less gas reaching the gas system, and quicker build-up of carbon on your BCG. We recommend cleaning your upper assembly 2-3 times more often when shooting steel ammo.
Wear and Tear
Running steel ammo through your complete rifle can cause quicker wear and tear to your AR-15 upper receiver and parts. A combination of steel being harder than brass and the unique case dimensions of 7.62x39 have caused problems with mil-spec extractors in the past. To address this issue, Bear Creek Arsenal upgraded their 7.62x39 bolts to be the same as those used for 12.7x42 uppers. As a general rule, steel-cased ammo is harder on AR-15 components and can decrease the longevity of a firearm.
Is Steel Case Ammo Worth It?
Steel cased ammo will continue to be a hot topic as ammunition remains scarce, expensive, and hard to find. While steel cased ammo can be much cheaper than brass, many argue that the increased dirtiness, wear and tear, less accuracy, and cycling issues negate the initial cheaper price. Additionally, brass ammunition can be reloaded if you have the necessary equipment while steel cases are generally not reloaded. We at Bear Creek Arsenal do not recommend using steel ammunition in your complete firearm or upper assembly, but understand if the availability and cheaper price do cause you to try it out. That's why we provide content like this to show you the pros and cons of each and inform you as to how to run steel ammo reliably. To see more real-world data comparing steel case ammo and brass cased ammunition, check out Lucky Gunner's epic torture test. Be sure to browse our selection of enhanced 7.62x39 complete uppers and 7.62x39 AR-15 Rifles. Comment you're opinion of steel ammunition below and check out our other helpful articles like 7.62x39 vs 308 and AR Pistols guide!