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Old 04-17-2019, 06:54 PM   #1
Icelander
 
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Default Iron Content of Rifle Ammo (SS109/M855, M59, M61, M80, M855A1, etc.)

Many common military rifle rounds contain iron in the form of steel of various hardness. This can be present in the jacket (e.g. several types of 7.62x51mm ammo) and/or as a steel penetrator in a lead or copper bullet (the SS109/M855 NATO 5.56x45mm round, the newer M855A1, etc.). Older or less expensive AP bullets may be mostly constructed from hardened steel, as opposed to the more expensive and harder metals used for APHC rounds.

In a Monster Hunting campaign where fey, manifested spirits and various other types of foes are suspectible to iron, it matters to me how much of the bullet is composed of iron and how much of mystically irrelevant substances like lead, as I plan to make such projectiles proportionally less effective (in terms of Weakness and Vulnerability) the less iron they contain.

As far as I could find, lead-free M80A1 rounds in 7.62x51mm weigh 130 grains to the 144-147 grains of the standard M80 FMJ (with lead projectiles). They are noted as saving 114.5 grains of lead per round, implying that about 15-20% of the weight of a typical M80 FMJ round is something other than lead, i.e. the jacket. The M855A1 in 5.56x45mm weighs 62 grains and the steel penetrator seems to be 19 grains of that.

Does anyone have an idea how much of the projectile weight in the following rounds consists of iron?

5.56x45mm

SS109/M855: 61-62 grains. A Semi-Armor-Piercing round, with a penetrating steel core, but presumably most of the weight consisting of lead. The steel penetrator weighs about 10 grains and the standard jacket in US-made M885 seems to weight 19.8 grains. The lead core of M885 rounds weighs 32 grains.

M855A1: 62 grains. A lead-free replacement for the standard US ball ammo, replacing lead with copper (increasing bullet length to keep weight the same). Has a different steel penetrator than the M855, which seems to increase AP performance. Wikipedia tells me the steel penetrator is 19 grains of the total projectile.

M318: 62 grains. Developed for US Special Operations Forces, optimized for shorter barrels, barrier-blind. Open tip, lead core, solid brass rear. As far as I can tell, no iron.

5,6mm Gw Pat 90: 63 grains. Swiss issue round.Tombac jacketed lead alloy projectile. AFAIK, no iron.

DM11: 63 grains. German issue round. Dual core ball cartridge with steel core.

7.62x51mm

M59: 150.5 grains. Semi-Armor-Piercing iron or mild steel core and a gilded steel jacket. Seems to have at least 60% iron content.

M61: 150.5 grains. Black-tip, AP rounds. As far as I can tell, largely made from hardened steel. Similar ammunition, like P80 or CBC NATO AP often sold as 'M61 equivalent', with variations in penetrator design being the rule more than the exception. Penetrator weights I've found are 58-71 grains, so iron content will range from 38-67%, depending on whether there is any lead in the bullet, whether the jacket is gilded metal or copper-washed steel and whether it's the same thickness as ball ammunition or thicker.

M80: 147 grains. Standard US FMJ. About half such ammo bought as military surplus will have bimetallic jackets containing some measure of steel, but given that the jackets weigh 32-34 grains or so and some of that will be copper or other softer material, it's unlikely that this will push it much above 10% iron content. This also applies fairly generally to 7.62x51mm military ammunition, in that if there is no steel core, the iron content is probably below 15%.

M80A1: 130 grains. Lead-free FMJ, copper.

MK319 MOD 0: 130 grains. Enhanced performance, barrier blind, etc.

Patrone AB22, 7.62mm × 51, DM41, Weichkern: . 146-147 grains. Early German M80 equivalent. Copper-washed steel jacket.

Patrone AB22, 7.62mm × 51, DM111, Weichkern: 147 grains. Later German M80 equivalent. Cupronickel-coated steel jacket.

Patrone, 7.62mm × 51, DM111A1: 144-147? grains. Development of DM111. Different metal jacket. Copper base.

Patrone, 7.62mm × 51, DM111A2: 144-147? grains. Further development of DM111.

Patrone , 7.62mm × 51, DM151, AP/Hartkern: 151 grains.Tungsten carbide core, cupronickel-coated steel jacket.

SalTech FMJ: 150 grains. Swiss military ball ammo.

If an organization or, say, a Latin American country, wanted to have weapons with high iron content projectiles, which type of common military ammunition should they try to get licensing to manufacture locally?
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Last edited by Icelander; 04-23-2019 at 07:15 PM.
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