From: Prof. Andrew Woolard, research department, Chinook 91 GSO station
To: RADM William Carson, deputy commander of the 4th Colonial Marine Division
Clearance: Secret
RADM the report you commisioned is now complete. Our research team has tirelessly worked round the clock on this for two weeks since that last incident. Certain areas still require additional research and this in turn requires more samples, but I'm mostly satisfied with the current result. A copy is attached to this email.
I'd be interested in hearing from you shortly.
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Prof. Andrew Woolard, PHD
Head of advanced weapons research,
USCM Research Department
Effectiveness of USCM service small arms ammunition against the XX121 armor
By Dr Andrew Woolard, PHD, Dr Fenton Werner PHD, LCDR Corbin Feufer MSC
Rev. A
2190 June, 3rd.
Introduction
After the few recent incidents, the final of which was the battle on planet LV-4624, USCM 4rd division commissioned this report to test the effectiveness of different small arms currently in service by the USCM against the armored specimens of XX121 species.
The xenomorphs has shown the extreme resilience to the small arms fire and this report would hopefully be useful for decision makers within the force in working to implement different doctrinal, tactical, logistical and training changes required for us to face this new threat.
Methodology
Weapon damage is given in the standard munition comparison units used by the USCM armament procurement department, or USCMAPDSMCUs for short.
Xenomorph caste and strain reporting names are given in accordance with the nomenclature published by the USCM Standardization Coordinating Committee in document #31778.
Due to lack of standardized units for measuring biological armor, our team had to improvise. After some discussion we noticed that the cell structure of XX121 armor is not extremely similar to the polymer possessed by Herculian mud beetle(Scarabaeinae Herculi) and we settled on using the second abdominal segment of Scarabaeinae Herculi as a relative standard of armor. When the report says that a Crusher has 40 armor, it means that it has the armor of 40 bug abdominal segments tied together.
Penetration is another unit our team had to create. One unit of penetration is the force generated by penetrating 1/12 of an inch into the second abdominal segment of Scarabaeinae Herculi with M10 bayonet when done by a second generation synthetic unit using 4% of it's upper body muscle mass.
Weapon discussions follow the format of data first, then recommendations and then additional notes and applicable discussion, if any.
Xeno armor per caste
Here's a list of xenos sorted by their practical maximum armor:
Ravager Hedgehog = 50
Crusher = 40
Defender = 40
Praetorian Oppressor = 35
Queen = 30
Praetorian Warden = 30
Burrower = 30
Praetorian Base, Dancer = 25
Ravager Base, Berserker = 25
Spitter = 25
Warrior = 20
Hivelord = 20
Carrier = 20
Drone = 20
Runner = 0
Sentinel = 0
Boiler = 0
Lurker = 0
Primary weapons
Per weapon data should be interpreted in this way: "50 armor: 7 damage, 85% reduction" means that against a target with 50 armor the current munition does 7 damage, which 85% reduction from the base damage.
M41
With M41 using AP for anything with over 20 armor is recommended.M41 normal bullet damage is 51
50 armor: 7 damage, 85% reduction
40 armor: 13 damage, 72% reduction
35 armor: 17 damage, 65% reduction
30 armor: 21 damage, 58% reduction
25 armor: 25 damage, 50% reduction
20 armor: 29 damage, 41% reduction
M41 AP damage is 31 and penetration is 31
50 armor: 16 damage, 45% reduction
40 armor: 26 damage, 15% reduction
35 armor: 28 damage, 7% reduction
<=31 armor: 31 damage, 0% reduction
M39
M39 AP should be used for any armored targets.M39 normal ammo damage is 47
50 armor: 5 damage, 88% reduction
40 armor: 11 damage, 74% reduction
35 armor: 15 damage, 67% reduction
30 armor: 19 damage, 59% reduction
25 armor: 22 damage, 51% reduction
20 armor: 27 damage, 42% reduction
M39 AP damage is 34 and penetration is 34
50 armor: 21 damage, 38% reduction
40 armor: 30 damage, 10% reduction
35 armor: 33 damage, 1% reduction
<=34 armor: 34 damage, 0% reduction
M39 AP ammo is actually superior to M41 AP, while normal ammo is inferior to it. All of this combined makes M39 AP superior even for dealing with 20 armor targets. The two recent after battle reports(documents #35147 and #36332) had shown that multiple surviving soldiers developed a high preference for M39 AP. Our research seems to validate their experience.
L42
L42 AP ammo should be used for targets with 25 armor and more.L42 normal ammo damage is 65
50 armor: 12 damage, 80% reduction
40 armor: 20 damage, 68% reduction
35 armor: 24 damage, 62% reduction
30 armor: 29 damage, 55% reduction
25 armor: 34 damage, 47% reduction
20 armor: 44 damage, 31% reduction
L42 AP damage is 40 and penetration is 40
50 armor: 23 damage, 42% reduction
40 armor: 33 damage, 15% reduction
35 armor: 37 damage, 7% reduction
<=31 armor: 40 damage, 0% reduction
L42 normal rounds slightly outperforms the AP ammo at targets with 20 armor. This is due to it having a superior stopping power.
HPR
HPR uses the same non-AP M41 bullets and in this has an indistinguishable ballistic performance.
Smartgun
Smartgun armor shredding bullets outperform high precision on targets with 25 armor or more. Xenomorph queens should be prioritized by smartgunners firing armor shredding ammunition.Smartgun high precision rounds damage is 43, penetration 0
50 armor: 4 damage, 90% reduction
40 armor: 10 damage, 76% reduction
35 armor: 13 damage, 69% reduction
30 armor: 16 damage, 60% reduction
25 armor: 20 damage, 52% reduction
20 armor: 24 damage, 43% reduction
Smartgun armor shredder damage 22, penetration 36, damage falloff 0.8
50 armor: 13 damage, 39% reduction
40 armor: 20 damage, 7% reduction
<=36 armor: 22 damage, 0% reduction
See the general discussion section for additional information on armor shredding.
Pistols
Since our team has used up all available xenomorph samples, we could not do the proper testing of pistol ammunition. Additional samples and research is needed in this area.
Discussion
One important moment that should not be overlooked is the problem of identifying strains of a particular xenomorph caste. Such identification can be problematic even for a trained xenobiologists and seems nigh impossible for a soldier in combat. For example normal Praetorians with 25 armor receive 25 damage with a normal M41 bullet and 31 with AP. In this case the normal bullet is doing only 80% of AP bullet damage, which may be acceptable. But if a soldier misidentifies the Praetorian and is actually shooting at an Oppressor, the normal bullet does just 17 damage, while AP does 28, so it's just 60%. Same thing exists for Ravagers, with one discovered strain(Hedgehog) is more highly armored than the rest.
Some of the highest armored T3 specimens, Crushers and Hedgehog Ravangers had shown extreme resilience to normal ammunition. Using AP ammunition when dealing them is extremely important. For crushers for example AP ammunition generally does double damage, across all of the weapons tested by our team.
The previous report on the use of small arms against xenomorphs, Alvarado et al.(document #23617) recommended using normal ammunition over armor piercing due to a belief that the superior armor shredding potential of the normal ammunition would lead to better combat results as opposed to counting on being able to burst damage the specimens down. Out team has uncovered that the new T3 samples show extreme armor durability and marines should not expect to strip it in any realistic scenario. As such we see the need of rescinding that recommendation. The Queen on the other hand still has high, but not durable armor and this is why we recommend considering her a priority target for smartgunners firing armor shredding ammunition.
Our recommendations ignore the possible scarcity of AP ammunition and as such we need to underscore the importance of a proper and working logistical system.
Since our finding mostly confirm the usefulness of armor piercing ammunition, we see the need to underline the importance of soldiers practicing with it, since the use of such ammunition may change important ballistic parameters of some weapons, like accuracy.
Spoiler: