一直有人说，中国为了节约铜资源，而在中国轻武器大量使用钢壳子弹，这导致性能比起美国的黄铜弹壳有所下降，那么，真实情况确实是这样的吗？

从火药武器诞生以来，再装填效率和可靠性一直是火器专家考虑的重中之重。早在五百年前，各国就开始对再装填提出各种设想。

以上都是历史中解决火炮/火枪发射速度采用的各种工具，不过我们大家都知道，自从金属壳定装子弹出现后，在步兵轻武器中，已经基本淘汰了以上所有的定装药技术。那么，就让我们回归正题，看看现代几种材质的弹壳的优劣势。

本文主要翻译自Brass vs. Steel Cased Ammo – An Epic Torture Test 作者  Andrew

原文地址：https://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/

We conducted this testing in the Arizona desert during monsoon season. Dust storms frequently interrupted our range trials. These storms covered the carbines in fine sand and we also saw rainstorms drench the carbines in water. These storms did not affect the previously set cleaning schedule. In addition, we shot at a high rate of fire. We fired the carbines until they were too hot to touch at times during the test. These rates of fire were identical for all weapons and they continued to function very well despite the adverse conditions.

测试地点为亚利桑那州，遭受了多次沙尘暴袭击，同时还遭受了沙漠特有的骤雨，不过团队刻意不清理步枪，一直使用全自动模式测试，直到枪管通红无法握持才会暂停，以此考验步枪在高射速、高污染环境下使用不同弹壳的性能。

At the 5,000 round mark, we cleaned the bolt carriers, upper receivers, and barrels. After we noted inconsistent cycling thanks to the aid of high speed video, we replaced the action springs ($3). We also pulled out and replaced the extractor springs ($6.99) and gas rings ($2.19).

测试团队每隔5000发清洗一次枪械，并更换部分易损零件，主要是导气管结构。

测试团队选择若干把同一批次步枪，修正故障后（原步枪滚筒螺母扭矩值不合适，导致精度由3.5moa正常水平放大到5moa），分别测试10000发黄铜壳弹（federal），10000发覆铜钢弹（wolf），10000发钢壳（tula），得出了以下结论：

• Federal（黄铜）: 10,000 rounds, 0 malfunctions（故障）.

• Brown Bear（覆铜钢，乌克兰或俄罗斯代工）: 10,000 rounds, 9 malfunctions (5 stuck cases（子弹卡住）, 1 magazine-related failure to feed（弹匣故障）, 3 failures to fully cycle（导气运作不良）)

• Wolf（覆铜钢，乌克兰或俄罗斯代工）: 10,000 rounds, 15 malfunctions (stuck cases（卡弹）)

• Tula（钢壳，俄罗斯图拉兵工厂）: DNF (6,000 rounds in alternate carbine, 3 malfunctions)

  
  

• The carbine firing Tula had a case stuck in the chamber after 189 rounds. This proved exceptionally difficult to clear, even with the use of a steel cleaning rod after the rifle had cooled. Over the next three hundred rounds, we encountered 24 malfunctions total. These problems consisted of stuck cases and failures to fully cycle, or “short stroking.” At this time, we pulled the Tula carbine from the testing. The delays caused considerable problems and put the entire project’s completion in peril.

  翻译如下：图拉的钢壳弹在使用大毒蛇XM15发射189发后即卡住，难以排除；使用它继续发射300发，有24发故障，要不是卡壳，要不就是气动机工作不正常。

从初步结论看，似乎是黄铜壳表现最为理想，10000发无故障，而覆铜钢故障率约千分之1.5，钢壳的图拉兵工厂版本则表现不良。但是需要记住的是，5.56因为锥度较小，所有的美国军标子弹均是黄铜壳（federa就是美国军标弹），有利于抽壳；使用钢壳后，阻力比较大，所以，美国团队考虑到这个问题后，改变了测试工具：

We decided to fire the remainder of the Tula ammunition through other carbines. We cycled approximately 300 rounds through an HK416 (no malfunctions), 1,000 through a Spike’s Tactical carbine (3 malfunctions), and 6,000 through a Spike’s Tactical midlength without any cleaning (3 malfunctions). Stuck cases or failures to eject accounted for all those malfunctions.

测试团队更换为短行程活塞的HK 416后，发射300发无故障；使用spikestactical的卡宾枪发射1000发，3发故障；又用spikestactical的中等长度步枪发射6000发（不清理枪械），仅3发故障。由此可见，采用了制造更加精良的枪械后，发射钢壳弹的可靠性不亚于覆铜钢子弹。

Of the remaining three ammunition brands, the first malfunction encountered was a magazine-related failure to feed at 2250 rounds with the Brown Bear carbine. For the Wolf carbine, the first malfunction occurred at 4850 rounds – a stuck case.

两种覆铜钢子弹在大毒蛇XM-15表现良好，棕熊牌（俄罗斯或乌克兰代工）2250发出现第一次故障，狼牌（俄罗斯或乌克兰代工）在4850发出现第一次故障。

The second half of the test started off with short stroking malfunctions from the Brown Bear carbine. This occurred at 5,200 and 5,250 rounds. High speed video showed that the bolt was barely coming back far enough to pick up the next round. It occasionally wouldn’t travel far enough to eject the spent case. Additional lubrication did not prevent the second malfunction.

A detailed physical examination revealed previously unnoticed carbon buildup in the gas key and gas tube which had almost completely occluded those components. We inspected the other firearms. We didn’t see carbon buildup that was remotely close to that of the Brown Bear carbine. It was difficult to clean these components in the field. So, we decided to them aside in order to examine the phenomenon.

We replaced the gas tube and bolt carrier of the Brown Bear rifle with identical components. After the swap, we resumed firing without incident.

No malfunctions occurred until 7,500 rounds. We ran into five stuck cases between 7,500 and 8,200 rounds. From 7,500 rounds on, we observed a number of cases with distended and/or split necks.

The last malfunction with Brown Bear was a cycling issue similar to the first two. This happened at the 9,551 round mark. A change in report and recoil indicated that the round was possibly undercharged, although the projectile did exit the bore.

We encountered two more stuck cases with the Wolf carbine at 5,800 and 5,850 rounds. We didn’t take actions and didn’t get another stuck case until the round count passed the 9,000 mark. From 9,200 to 10,000 rounds, we observed twelve stuck cases. During this time, we used a Boresnake to superficially clean the bore and chamber. It did not appear to have any impact on the occurrence of malfunctions.

As stated previously, the carbine firing Federal ammo functioned flawlessly from the first round to the last. There is not much else to report in terms of reliability. It just worked.

覆铜钢子弹在5000发时故障率开始增加，9000发以上时，枪械故障率激增，9200-10000发时在大毒蛇步枪被记录出12次卡壳故障。黄铜子弹10000发无问题。由此可见，在5.56枪械上，黄铜壳可靠性明显优于钢壳弹。

（当然，美俄火药配方，弹头材质也有差别）

枪弹洁净度测试：

Is Brass or Steel Cased Ammo Dirtier?

Of particular concern to some shooters is whether or not one type of ammo is dirtier than another. Shooters often malign imported ammunition for being dirty and difficult to clean. So, we didn’t clean lower receivers of each firearm at all from the first shot to the last, in order to see which became the most filthy.

Interestingly, the dirtiest lower receiver was that of the Federal carbine. It took us significantly longer to clean the upper receiver and bolt carrier group assembly of the Federal carbine than the Brown Bear and Wolf carbines. Although you should keep in mind that carbon fouled the Brown Bear carbine’s gas tube and gas key so much after 5,000 rounds that it would no longer function reliably. We observed nearly the same level of buildup on the replacement key and tube after they fired just short of 5000 rounds.

AR-15采用气吹式结构，两种独联体生产的覆铜钢子弹使用的火药在5000发后堵塞了导气管，而federal则大量沉积在气吹室，可见美俄配方的差异性。

精度维持（热散）测试：

While the carbine firing Federal ammunition maintained acceptable accuracy up to and including the 10,000 round mark, the Brown Bear and Wolf carbines exhibited significant accuracy loss by the 6,000 round mark. It is quite possible that this first started occurring earlier than 6,000 rounds, because groups at 4,000 were well within standards of 5MOA or less, while some shots at 6,000 “keyholed,” or impacted the target sideways.

Even if we use accuracy as the only factor to determine serviceability, the Federal carbine was by far the best performer in this category. Its barrel was showing wear, but was serviceable right up to the end of the test. The Brown Bear and Wolf barrels would have required replacement at approximately 5,000 rounds, or halfway through the test.

美国军标黄铜壳federal能够10000发都维持在5moa的基准水平之内，而两种覆铜钢的子弹在6000发出现热散，但头4000发时覆铜钢表现和黄铜没有明显差异。此外，5000发时两种覆铜钢子弹的步枪导气管已经堵塞，并且枪膛磨损严重，必须更换，可能是这两种子弹被甲较硬，对膛线磨损较大（俄罗斯广泛使用钢背甲，而美国民用步枪一般都是设计为黄铜背甲）。所以不推荐高硬度背甲子弹连续在XM-15使用5000发。

团队对数据的分析：

Why Didn’t Tula Function Well in the Test Carbine?

One of the first questions one might have after reading the above treatise is, “What happened with Tula?”

After all, it consists of a 55 grain bimetal jacketed lead core projectile loaded in a polymer coated steelcase. This description is by no means an outlier compared to the other ammunition in the test. In terms of velocity, Tula was also in line with the other products. Tula functioned very well in a Spike’s Tactical midlength, which saw 6,000 rounds of Tula without any cleaning and only had three malfunctions.

But in the Bushmaster carbine, Tula was a no-go. In terms of functional problems, there were two major issues with Tula: “short stroking” – a failure of the bolt to fully cycle to the rear – and extraction problems. Further research and experimentation indicated that there was likely one factor which contributed to both failure types.

What’s really important in this case, however, is not the maximum chamber pressure number, but powder burn rate and thus gas port pressure. Whether measured in clean, fouled, new, or worn out barrels, Tula exhibited gas port pressures that were 10-20% lower than all other ammunition types.

Basically, the powder burns too fast, and by the time the bullet has reached the barrel, the pressure drops.  The rise time of Tula, defined as the time in microseconds for pressure to rise from 25% to 75% of maximum chamber pressure, is 175ms. In comparison, Federal AE223, depending on temperature, has a rise time of 260-300ms.

这段文字可以简单解释如下：图拉的子弹配方采用了高燃速火药，而且颗粒研磨程度并不均匀（国内2015年对10式子弹评价也有类似的语句，颗粒大小不均是5.8子弹散步较大的原因之一），而XM-15是根据美国黄铜壳设计的步枪，因此在采用高燃速火药的钢壳子弹时，由于火药燃速大，初始膛压高，但进入导气管后气压急剧下降，导致推动枪机力量减弱无法抽壳。不过，由于图拉采用的是俄罗斯军标配方，在使用长行程活塞的AK-74和短行程活塞的HK 416时，因为气室较小且靠近枪管，所以在有活塞的步枪上不会出现抽壳力不足问题。

子弹膨胀性测试：

Part of the answer to this question is the nature of the case material itself. When heated, steel does not expand and contract the same way that brass does – in fact, brass expands 1.5 times as much as steel. The shape of the .223/5.56 case was designed with brass as the case material; this plus the fact that steeldoesn’t expand – and more importantly, contract – like brass means that extraction will be naturally more difficult.

黄铜形变性是钢的1.5倍，由于美国5.56原来设计即采用黄铜弹壳，因此一般AR-15不适合换用膨胀性差的钢壳弹，否则抽壳阻力太大。

（相比之下，国内5.8子弹一开始就是按钢壳或覆铜钢壳设计，如果贸然改成黄铜，可能导致抽壳力过大导致弹壳碎裂）

What Effect Do Coatings Have On Steel Cased Ammo Performance?

A common belief is that the lacquer coating of certain steel cased ammunition will “melt” in the chamber of a hot rifle and cause subsequent rounds to fail to extract. At one point, we might have believed that.

But in this test, we saw three times as many failures to extract with the polymer coated Wolf brand ammo (15 extraction failures) than with the lacquer coated Brown Bear ammo (5 extraction failures). Although we fired the polymer coated Tula ammunition in different rifles, the rate of extraction failures in those rifles was lower than that of Wolf.

事实证明，涂有聚合物的钢壳子弹故障率反而是涂漆钢的5倍。因此钢壳涂聚合物并不会带来任何润滑效果，反而会在高温下加剧故障。