09-04-2017, 10:27 PM | #1 |
Join Date: Jul 2005
Location: Holiday, FL
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Statting 5.56x45mm ball; M855A1
M855 from a 14.5" M4 barrel is 4d+2 pi.
Despite the steel penetrator, it's not considered armor piercing. This is mostly because the 600m distance to punch the DR 4 of a steel pot is well within the 800 yard 1/2D distance of the 5d pi from the 20" M16A2 barrel and the 750 yard 1/2D distance for the M4. The minimum damage from both an M4 and M16A2 penetrate that helmet. The 1/2D for M193 from an M16A1 is 500 yards, the minimum damage from 5d pi won't penetrate now. With me so far? From the physical description of the M855A1 bullet, it conforms to how High Tech describes TL6 Armor-Piercing (AP) ammo. That would change the damage to 4d+2(2) pi-. The problem with this is M855A1 appears to perform no better against armor or barriers than M855 and is comparable to M80 ball in tissue. pi- would be worse soft tissue performance than before when the reports are saying it's better. 7.62x51mm NATO M80 ball is 7d pi. M855A1 fired from an M4 is reportedly doing comparable soft tissue damage to M80. OK. Giving M855A1 hollow-point status brings the damage to 4d+2(0.5) pi+. 7d pi does 7-42 points of damage. 24 average. 4d+2 pi+ does 9-39 points. 24 average. That is comparable. The niggling problem now is the (0.5) armor divisor for going hollow-point. By all accounts, M855A1 doesn't behave differently than M855 against barriers or armor. (0.5) would give unarmored targets DR1 and would double the DR of armored targets. Thus 4d+2(0.5) pi+ shouldn't penetrate the, now, DR 8 of a steel pot with minimum damage. Yet, it does. The way the round appears to behave is 4d+2 pi+. Not sure what generic label to apply to it here though or what it should do to the cost per shot, especially since it's shaping up to be not a lot more expensive than M855. This going to matter because they're applying this technology to 7.62 as well in the M80A1 round. One way to explain it can come from M855 being the US version of FN's SS109, which was developed in the 1970's, and is thus a TL7 round, 1980 being the cut-year between TL7 and TL8. Thus M855A1 is a TL8 round. There's only three TL8 kinetic energy bullet types listed in High Tech and they're all depleted uranium armor piercing rounds. I think I shall call it: Enhanced Performance Ball (EPB) (TL8) This ammo is made from a hardened steel tip with a lighter metal core and is designed to cause more damage to soft tissues via tumbling and fragmentation, without sacrificing penetration against armor or barriers. Change damage type: pi- becomes pi, pi becomes pi+, and pi+ becomes pi++ (no effect on pi++). Multiply CPS by 1.2. LC2.
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09-05-2017, 06:11 AM | #2 |
Doctor of GURPS Ballistics
Join Date: Sep 2004
Location: Lakeville, MN
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Re: Statting 5.56x45mm ball; M855A1
I went through a similar process with the Mk318 alternative:
https://gamingballistic.com/2016/01/...m-mk318-mod-0/
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09-05-2017, 07:46 AM | #3 |
Join Date: Jun 2016
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Re: Statting 5.56x45mm ball; M855A1
What ammo was used to get 800 and 750 yard half damage ranges for the M16A2 and M4? What's your source for a 500 yard half damage range for M193?
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09-05-2017, 08:39 AM | #4 |
Join Date: Jul 2005
Location: Holiday, FL
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Re: Statting 5.56x45mm ball; M855A1
GURPS: High Tech 4th Edition is where I got the 1/2 damage ranges.
Page 117 for the M16A2, where it also mentions the change from .223 Remington to 5.56x45mm NATO. Page 120 for the M16A1's range stats. Page 120 for the M4A1's stats. The M16A1 uses M193, the M16A2, M4 and M4A1 use M855.
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A hobbyist is an expert in their hobby. Unaccredited to be sure, but an expert nonetheless! Last edited by Z09SS; 09-05-2017 at 08:44 AM. Reason: I did not realize we needed to academically source references here now. |
09-05-2017, 09:30 AM | #5 |
Join Date: Jun 2016
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Re: Statting 5.56x45mm ball; M855A1
One note is that the standard for M193 was a steel helmet at 500 yards and M855 required penetrating that helmet at 800 meters or 874 yards. GURPS M855 doesn't pass NATO standards!
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09-05-2017, 09:54 AM | #6 | |
Join Date: Aug 2007
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Re: Statting 5.56x45mm ball; M855A1
Quote:
It is APHC that does full damage with the (2).
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09-05-2017, 03:44 PM | #7 | |
Join Date: Jan 2014
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Re: Statting 5.56x45mm ball; M855A1
M855A1 ballistic gel test: https://youtu.be/d8IvDPuVuho
M80A1 ballistic gel test: https://youtu.be/yW-jlvNQA8w In real life, the M855A1 ball ammo is superior to M855 ball ammo due to much quicker, and more consistent, fragmentation when coming out of either 14.5-inch barrels, like those of the M4A1, or out of 20-inch barrels, like those of the M16A4. It is less velocity dependent compared to the original M855 ball ammo. http://www.thefirearmblog.com/blog/2...the-real-deal/ Quote:
Last edited by warellis; 09-05-2017 at 04:01 PM. |
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high-tech, modern firepower |
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